Lux expression in cells and methods of use

Abstract

The present disclosure relates to cells, including stem cells, comprising an autobioluminescent phenotype, wherein the cells emit a luminescent signal in the absence of an exogenous luminescent stimulator. The luminescent signal may be constitutive, inducible, repressible, or tissue-specific. The cells express a synthetically engineered bacterial luciferase (lux) cassette, i.e., the luxCDABEfrp gene cassette. The cells may comprise luxA, luxB, luxC, luxD, luxE, and flavin reductase. The cells may each express a combined expression level of luxC, luxD, luxE, and flavin reductase that is from ten to forty times greater than a combined expression level of luxA and luxB. Further, methods of making and using the cells comprising an autobioluminescent phenotype are disclosed herein.

What is claimed is: 
     
         1 . A stem cell comprising an autobioluminescent phenotype comprising a luminescent signal in the absence of an exogenous luminescent stimulator. 
     
     
         2 . The stem cell of  claim 1 , further comprising luxA, luxB, luxC, luxD, luxE, and flavin reductase. 
     
     
         3 . The stem cell of any one of  claims 1 - 1 , further comprising nucleic acids encoding each of luxA, luxB, luxC, luxD, luxE, and flavin reductase. 
     
     
         4 . The stem cell of any one of  claims 1 - 2 , wherein the luminescent signal is constitutively emitted. 
     
     
         5 . The stem cell of  claim 3 , wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid is operatively linked to at least one constitutive promoter. 
     
     
         6 . The stem cell of  claim 5 , wherein the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are each operatively linked to a constitutive promoter. 
     
     
         7 . The stem cell of  claim 4 , wherein the luxA nucleic acid and the luxB nucleic acid are operatively linked to a first constitutive promoter. 
     
     
         8 . The stem cell of  claim 7 , wherein the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are operatively linked to a second constitutive promoter. 
     
     
         9 . A kit for producing a stem cell having an autonomous luminescent phenotype, comprising:
 at least one vector comprising at least one of a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid.   
     
     
         10 . A method for producing a stem cell having autonomous and constitutive luminescence, comprising:
 providing a stem cell; and   transfecting the stem cell with at least one vector comprising at least one of a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid.   
     
     
         11 . Any one of  claim 8  or  9 , wherein the at least one vector comprises:
 a first vector comprising a luxA nucleic acid; 
 a second vector comprising a luxB nucleic acid; 
 a third vector comprising a luxC nucleic acid; 
 a fourth vector comprising a luxD nucleic acid; 
 a fifth vector comprising a luxE nucleic acid; and 
 a sixth vector comprising a flavin-reductase nucleic acid, 
 wherein one or more of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic acid are operatively linked to a constitutive promoter. 
 
     
     
         12 . Any one of  claim 8  or  9 , wherein the at least one vector comprises:
 a first vector comprising:
 a luxA nucleic acid and a luxB nucleic acid, wherein the luxA nucleic acid and the luxB nucleic acid are operatively linked to a first constitutive promoter; and 
 
 a second vector comprising:
 a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, and wherein the luxC nucleic acid, luxD nucleic acid, luxE nucleic acid, and flavin reductase nucleic acid are operatively linked to a second constitutive promoter. 
 
 
     
     
         13 . The method of any one of  claims 9 - 12 , wherein after the stem cell is transfected with the at least one vector, the stem cell expresses luxA, luxB, luxC, luxD, luxE, and flavin reductase. 
     
     
         14 . A method of real-time monitoring of cell population size of at least one stem cell, comprising:
 engineering the at least one stem cell to produce a constitutive luminescent signal;   measuring the constitutive luminescent signal emitted from the at least one stem; and   assessing the cell population size of the at least one stem cell based on the measured constitutive luminescent signal.   
     
     
         15 . The method of  claim 13 , further comprising tracking the cell population size over two or more points in time. 
     
     
         16 . A method of real-time monitoring of cell viability of at least one stem cell, comprising:
 engineering the at least one stem cell to produce a constitutive luminescent signal;   measuring the constitutive luminescent signal emitted from the at least one stem cell; and   assessing the cell viability of the at least one stem cell based on the measured constitutive luminescent signal.   
     
     
         17 . The method of  claim 15 , further comprising tracking the cell viability of the at least one stem cell over two or more points in time. 
     
     
         18 . The method of any one of  claims 13 - 16 , wherein the measurement of the constitutive luminescent signal emitted from the at least one stem cell correlates with the cell viability of the at least one stem cell. 
     
     
         19 . A method for measuring an effect of an agent on at least one stem cell, comprising:
 engineering the at least one stem cell to produce a constitutive luminescent signal;   contacting the at least one stem cell with an agent;   measuring the constitutive luminescent signal emitted from the at least one stem cell after the at least one stem cell is contacted with the agent; and   determining the effect of the agent based on the measured constitutive luminescent signal.   
     
     
         20 . The method of  claim 18 , further comprising tracking the effect of the agent over two or more points in time. 
     
     
         21 . The method of any one of  claim 18  or  19 , wherein when the at least one stem cell ceases production of a constitutive luminescent signal, determining that the agent is fatal to the at least one stem cell. 
     
     
         22 . The method of any one of  claims 13 - 20 , further comprising comparing the measurement of the constitutive luminescent signal emitted from the at least one stem cell to a constitutive luminescent signal emitted from a control population. 
     
     
         23 . The methods of  claim 21 , wherein a decrease in the measured constitutive luminescent signal emitted from the at least one stem cell relative to the constitutive luminescent signal emitted from the control population is indicative of a negative change in cell viability of the at least one stem cell. 
     
     
         24 . The method of  claim 22 , determining that the effect of the agent is cytotoxic. 
     
     
         25 . The method of  claim 21 , wherein an increase in the measured constitutive luminescent signal emitted from the at least one stem cell relative to the constitutive luminescent signal emitted from the control population is indicative of a positive change in cell viability of the at least one stem cell. 
     
     
         26 . The method of  claim 24 , determining that the effect of the agent is therapeutic. 
     
     
         27 . The method of any one of  claims 18 - 25 , wherein the agent is assessed for drug discovery. 
     
     
         28 . Any one of the methods of any one of the  claims 13 - 26 , wherein the method is performed in high-throughput. 
     
     
         29 . A method for reagent-free in vivo imaging of at least one stem cell, comprising:
 engineering the at least one stem cell to produce a constitutive luminescent signal in the absence of an exogenously added substrate;   injecting the at least one stem cell into an organism; and   imaging the constitutive luminescent signal emitted from the at least one stem cell in the organism.   
     
     
         30 . The method of  claim 28 , further comprising measuring the constitutive luminescent signal, and determining a total number of the at least one stem cell present in vivo based on the measured constitutive luminescent signal. 
     
     
         31 . The method of any one of  claim 28  or  29 , wherein the organism comprises an animal, and wherein the at least one stem cell is injected intravenously, intradermally, or subcutaneously in the organism. 
     
     
         32 . The method of  claim 30 , further comprising, after the at least one stem cell is injected into the animal, tracking movement of the at least one stem cell within the animal. 
     
     
         33 . The method of any one of  claims 28 - 31 , wherein the exogenously added substrate comprises an aldehyde functional group. 
     
     
         34 . The method of any one of  claims 13 - 32 , wherein the at least one stem cell comprises:
 a first vector comprising:
 a luxA nucleic acid and a luxB nucleic acid, wherein the luxA nucleic acid and the luxB nucleic acid are operatively linked to a first constitutive promoter, and 
   a second vector comprising:
 a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein the luxC nucleic acid, luxD nucleic acid, luxE nucleic acid, and flavin reductase nucleic acid are operatively linked to a second constitutive promoter. 
   
     
     
         35 . The method of any one of  claims 13 - 32 , wherein the at least one stem cell comprises:
 a first vector comprising a luxA nucleic acid;   a second vector comprising a luxB nucleic acid;   a third vector comprising a luxC nucleic acid;   a fourth vector comprising a luxD nucleic acid;   a fifth vector comprising a luxE nucleic acid; and   a sixth vector comprising a flavin-reductase nucleic acid,   wherein one or more of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic acid are operatively linked to a constitutive promoter.   
     
     
         36 . The stem cell of any one of  claims 1 - 2 , wherein the luminescent signal is tissue-specific. 
     
     
         37 . The stem cell of  claim 36 , comprising:
 at least one vector comprising a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, wherein at least one of the nucleic acids is operatively linked to a tissue-specific promoter.   
     
     
         38 . A method for producing a stem cell comprising an autonomous luminescent phenotype comprising a tissue-specific signal, comprising:
 providing a stem cell; and   transfecting the stem cell with at least one vector comprising at least one of a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, wherein at least one of the nucleic acids is operatively linked to a tissue-specific promoter.   
     
     
         39 . The stem cell of any one of  claims 36 - 37 , wherein if the stem cell is differentiated to a tissue cell expressing the tissue-specific promoter, the tissue cell expresses luxA, luxB, luxC, luxD, luxE, and flavin reductase and emits an autonomous luminescent signal. 
     
     
         40 . A method of real-time differentiation reporting using at least one stem cell comprising an autonomous luminescent phenotype comprising a tissue-specific signal, comprising:
 providing the least one stem cell comprising:
 at least one vector comprising at least one of a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, wherein at least one of the nucleic acids is operatively linked to a tissue-specific promoter, and wherein if the at least one stem cell is differentiated to at least one tissue cell in which the tissue-specific promoter is expressed, the at least one tissue cell emits a luminescent signal; and 
   when the luminescent signal is emitted, measuring the luminescent signal emitted from the tissue cell to track differentiation of the at least one stem cell to the at least one tissue cell.   
     
     
         41 . The method of  claim 39 , further comprising tracking the differentiation of the at least one stem cell to the at least one tissue cell over two or more points in time. 
     
     
         42 . The method of any one of  claim 39  or  40 , wherein an emission of the luminescent signal reports an onset of the differentiation of the at least one stem cell to the at least one tissue cell. 
     
     
         43 . The method of any one of  claims 39 - 41 , further comprising assessing a total number of the at least one tissue cell based on the measurement of the luminescent signal. 
     
     
         44 . The method of any one of  claims 39 - 42 , further comprising determining the at least one stem cell differentiated to the at least one tissue cell based on the measurement of the luminescent signal. 
     
     
         45 . A kit for producing a stem cell comprising an autonomous luminescent phenotype comprising a tissue-specific signal, comprising:
 at least one vector comprising at least one of a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, wherein at least one of the nucleic acids is operatively linked to a tissue-specific promoter.   
     
     
         46 . The stem cell or kit of any one of  claims 36 - 44 , wherein the at least one vector comprises:
 a first vector comprising:
 a luxA nucleic acid and a luxB nucleic acid, wherein the luxA nucleic acid and the luxB nucleic acid are operatively linked to a tissue-specific promoter; and 
   a second vector comprising:
 a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, wherein the luxC nucleic acid, luxD nucleic acid, luxE nucleic acid, and flavin reductase nucleic acid are operatively linked to a first constitutive promoter. 
   
     
     
         47 . The stem cell or kit of any one of  claims 36 - 44 , wherein the at least one vector comprises:
 a first vector comprising a luxA nucleic acid;   a second vector comprising a luxB nucleic acid;   a third vector comprising a luxC nucleic acid;   a fourth vector comprising a luxD nucleic acid;   a fifth vector comprising a luxE nucleic acid; and   a sixth vector comprising a flavin-reductase nucleic acid,   wherein one or more of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic acid are operatively linked to a tissue-specific promoter.   
     
     
         48 . Any one of  claims 36 - 47 , wherein the tissue-specific promoter comprises a TNNT2 promoter. 
     
     
         49 . Any one of  claims 38 - 48 , wherein the tissue cell or the at least one tissue cell comprises a cardiomyocyte. 
     
     
         50 . Any one of  claims 10 - 48 , wherein a total amount of transfected vector comprising the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic is present at an amount of from ten to forty times greater than a total amount of transfected vector comprising the luxA nucleic acid and the luxB nucleic acid. 
     
     
         51 . Any one of  claims 10 - 48 , wherein a total amount of transfected vector comprising the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic is present at an amount of from twenty to thirty times greater than a total amount of transfected vector comprising the luxA nucleic acid and the luxB nucleic acid. 
     
     
         52 . Any one of  claims 10 - 48 , wherein a total amount of vector comprising the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic is transfected at an amount of from ten to forty times greater than a total amount of vector comprising the luxA nucleic acid and the luxB nucleic acid. 
     
     
         53 . Any one of  claims 10 - 48 , wherein a total amount of vector comprising the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic acid are transfected at an amount of from twenty to thirty times greater than a total amount of vector comprising the luxA nucleic acid and the luxB nucleic acid. 
     
     
         54 . The stem cell of any one of  claims 1 - 2 , wherein the luminescent signal is responsive to an analyte. 
     
     
         55 . The stem cell of  claim 54 , comprising:
 a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are operatively linked to at least one analyte-responsive response element.   
     
     
         56 . The stem cell of  claim 54 , wherein the stem cell further comprises at least one analyte-responsive reverse transactivator that, when exposed to the analyte, activates the at least one analyte-responsive response element,
 wherein activation of the at least one analyte-responsive response element causes transcription of the at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid that is operatively linked to at least one analyte-responsive response element.   
     
     
         57 . The stem cell of  claim 54 , wherein the stem cell further comprises at least one analyte-responsive transactivator that, when exposed to the analyte, does not activate the at least one analyte-responsive response element,
 wherein lack of activation of the at least one analyte-responsive response element results in no transcription of the at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid that is operatively linked to at least one analyte-responsive response element.   
     
     
         58 . A method of constructing a stem cell configured to emit an autonomous inducible luminescent signal in the presence of an analyte, comprising:
 providing a stem cell;   co-transfecting the stem with at least one vector comprising a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are operatively linked to at least one analyte-responsive response element; and   co-transfecting the stem cell with a second vector comprising at least one analyte-responsive reverse transactivator that that, when exposed to the analyte, activates the at least one analyte-responsive response element,   wherein activation of the at least one analyte-responsive response element initiates transcription of the at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid that is operatively linked to the at least one analyte-responsive response element.   
     
     
         59 . A method of constructing a stem cell configured to emit an autonomous repressible luminescent signal in in the presence of an analyte, comprising:
 providing a stem cell;   co-transfecting the stem cell with at least one vector comprising a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are operatively linked to at least one analyte-responsive response element; and   co-transfecting the stem cell with a second vector comprising at least one analyte-responsive transactivator that, when exposed to the analyte, does not activate the at least one analyte-responsive response element,   wherein no activation of the at least one analyte-responsive response element prevents transcription of the at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid that is operatively linked to the at least one analyte-responsive response element.   
     
     
         60 . A method of monitoring gene expression in at least one stem cell, comprising:
 producing at least one of the stem cell of any one of  claims 53 ,  54 ,  55 , or  56 ;   contacting the at least one stem cell with the analyte; and   measuring the luminescent signal emitted from the at least one stem cell after contacting the at least one stem cell with the analyte to monitor expression of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid.   
     
     
         61 . The method of  claim 59 , further comprising measuring the luminescent signal emitted from the at least one stem cell over two or more points in time. 
     
     
         62 . The method of any one of  claim 59  or  60 , further comprising assessing gene expression by comparing the measurement of the luminescent signal emitted from the at least one stem to a luminescent signal emitted from a control population. 
     
     
         63 . A method of determining a presence of an analyte in a sample, comprising:
 producing at least one of the stem cell of any one of  claims 53 ,  54 ,  55 , or  56 ;   contacting the at least one stem cell with the sample;   measuring the luminescent signal emitted from the at least one stem cell after contacting the at least one stem cell with the analyte to monitor expression of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid; and   assessing the presence of the analyte in the sample based on the measurement of the luminescent signal.   
     
     
         64 . The method of  claim 62 , further comprising comparing the measurement of the luminescent signal emitted from the at least one stem to a luminescent signal emitted from a control population. 
     
     
         65 . A kit for producing a stem cell emitting an autonomous luminescent signal inducible by an analyte, comprising:
 at least one vector comprising a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are operatively linked to at least one analyte-responsive response element; and   a second vector comprising at least one analyte-responsive reverse transactivator that, when exposed to the analyte, activates the at least one analyte-responsive response element.   
     
     
         66 . A kit for producing a stem cell emitting an autonomous luminescent signal repressible by an analyte, comprising:
 at least one vector comprising a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid are operatively linked to at least one analyte-responsive response element; and   a second vector comprising at least one analyte-responsive transactivator that, when exposed to the analyte, does not activate the at least one analyte-responsive response element.   
     
     
         67 . Any one of  claims 54 - 65 , wherein the at least one analyte-responsive response element comprises a tetracycline response element, preferably wherein the analyte comprises tetracycline or an analog of tetracycline. 
     
     
         68 . Any one of  claims 54 - 66 , wherein the at least one analyte-responsive transactivator or the at least one analyte-responsive reverse transactivator is operatively linked to a constitutive promoter, preferably wherein the constitutive promoter is a chicken beta-actin promoter. 
     
     
         69 . Any one of  claims 54 - 67 , wherein the at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid that is not operatively linked to at least one analyte-responsive response element is operatively linked to a constitutive promoter. 
     
     
         70 . A stem cell-derived autonomously luminescent cell, comprising:
 an autonomously luminescent eukaryotic cell differentiated from an autonomously luminescent stem cell, wherein the differentiated autonomously luminescent eukaryotic cell and the autonomously luminescent stem cell both express a constitutive luminescent signal in the absence of an exogenous luminescent stimulator.   
     
     
         71 . A method for producing a stem cell-derived autonomously luminescent cell from an autonomously luminescent stem cell, comprising:
 constructing an autonomously luminescent stem cell, and   differentiating the autonomously luminescent stem cell into the stem cell-derived autonomously luminescent cell, wherein the stem cell-derived autonomously luminescent cell emits a luminescent signal in the absence of an exogenous luminescent stimulator.   
     
     
         72 . The method of  claim 70 , wherein the differentiating is performed by small molecule method. 
     
     
         73 . A method of real-time monitoring of cell viability of at least one stem cell-derived autonomously luminescent cell, comprising:
 providing at least one stem cell-derived autonomously luminescent cell;   measuring the constitutive luminescent signal emitted from the at least one stem cell-derived autonomously luminescent cell; and   assessing the cell viability of the at least one stem cell-derived autonomously luminescent cell based on the measured constitutive luminescent signal.   
     
     
         74 . The method of  claim 72 , further comprising tracking the cell viability of the at least one stem cell-derived autonomously luminescent cell over two or more points in time. 
     
     
         75 . The method of any one of  claim 72  or  73 , wherein the measurement of the constitutive luminescent signal correlates with the cell viability of the at least one stem cell-derived autonomously luminescent cell. 
     
     
         76 . A method for determining an effect of an agent in at least one stem cell-derived autonomously luminescent cell, comprising:
 engineering the at least one stem cell-derived autonomously luminescent cell to produce a constitutive luminescent signal;   contacting the at least one stem cell-derived autonomously luminescent cell with an agent;   measuring the constitutive luminescent signal emitted from the at least one stem cell-derived autonomously luminescent cell after the at least one stem cell-derived autonomously luminescent cell is exposed to the agent; and   determining the effect of the agent based on the measured constitutive luminescent signal.   
     
     
         77 . The method of  claim 75 , further comprising tracking the effect of the agent over two or more points in time. 
     
     
         78 . The method of  claim 76 , further comprising determining a time point at which the effect of the agent stabilizes. 
     
     
         79 . The method of any one of  claims 75 - 77 , wherein when the at least one stem cell-derived autonomously luminescent cell ceases production of a constitutive luminescent signal, determining that the agent is fatal to the at least one stem cell-derived autonomously luminescent cell. 
     
     
         80 . The method of any one of  claims 72 - 78 , further comprising comparing the measurement of the constitutive luminescent signal emitted from the at least one stem cell-derived autonomously luminescent cell to the constitutive luminescent signal emitted from a control population. 
     
     
         81 . The method of  claim 79 , wherein a decrease in the measured constitutive luminescent signal emitted from the at least one stem cell-derived autonomously luminescent cell relative to the constitutive luminescent signal emitted from the control population is indicative of a negative change in the cell viability of the at least one stem cell-derived autonomously luminescent cell resulting from exposure to the agent. 
     
     
         82 . The method of  claim 79 , determining that the effect of the agent is cytotoxic. 
     
     
         83 . The method of  claim 79 , wherein an increase in the measured constitutive luminescent signal emitted from the at least one stem cell-derived autonomously luminescent cell relative to the constitutive luminescent signal emitted from the control population is indicative of a positive change in the cell viability of the at least one stem cell-derived autonomously luminescent cell resulting from exposure to the agent. 
     
     
         84 . The method of  claim 82 , determining that the effect of the agent is therapeutic. 
     
     
         85 . Any one of  claims 69 - 82 , wherein the autonomously luminescent stem cell comprises:
 at least one vector comprising at least one of a luxA nucleic acid, a luxB nucleic acid, a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, nucleic acid, and a flavin-reductase nucleic acid, and wherein the luxA nucleic acid, a luxB nucleic acid, luxC nucleic acid, luxD nucleic acid, luxE nucleic acid, and flavin-reductase nucleic acid are operatively linked to at least one constitutive promoter, and   wherein the autonomously luminescent stem cell expresses luxA, luxB, luxC, luxD, luxE, and flavin reductase.   
     
     
         86 . The preceding  claim 84 , wherein the at least one vector comprises:
 a first vector comprising:
 a luxA nucleic acid and a luxB nucleic acid, wherein the luxA nucleic acid and the luxB nucleic acid are operatively linked to a first constitutive promoter, and 
   a second vector comprising:
 a luxC nucleic acid, a luxD nucleic acid, a luxE nucleic acid, and a flavin reductase nucleic acid, and wherein the luxC nucleic acid, luxD nucleic acid, luxE nucleic acid, and flavin reductase nucleic acid are operatively linked to a second constitutive promoter. 
   
     
     
         87 . The preceding  claim 84 , wherein the at least one vector comprises:
 a first vector comprising a luxA nucleic acid;   a second vector comprising a luxB nucleic acid;   a third vector comprising a luxC nucleic acid;   a fourth vector comprising a luxD nucleic acid;   a fifth vector comprising a luxE nucleic acid; and   a sixth vector comprising a flavin-reductase nucleic acid,   wherein one or more of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin-reductase nucleic acid are operatively linked to a constitutive promoter.   
     
     
         88 . Any one of the preceding claims, wherein the stem cell-derived autonomously luminescent cell expresses luxA, luxB, luxC, luxD, luxE, and flavin reductase, such that the stem cell-derived autonomously luminescent cell luminesces in the absence of an exogenous luminescent stimulator. 
     
     
         89 . Any one of the preceding claims, wherein a combined production level of luxC, luxD, luxE, and flavin reductase ranges from ten to forty times greater than a combined production level of luxA and luxB. 
     
     
         90 . Any one of the preceding claims, wherein a combined production level of luxC, luxD, luxE, and flavin reductase ranges from twenty to thirty times greater than a combined production level of luxA and luxB. 
     
     
         91 . Any one of the preceding claims, wherein one or more of the nucleic acids encoding each of luxA, luxB, luxC, luxD, luxE has a greater than 80% sequence identity with the corresponding nucleic acid in  Photorhabdus luminescens.    
     
     
         92 . Any one of the preceding claims, wherein one or more of the nucleic acids encoding each of luxA, luxB, luxC, luxD, luxE has a 100% sequence identity with the corresponding nucleic acid in  Photorhabdus luminescens.    
     
     
         93 . Any one of the preceding claims, wherein the stem cell emits the luminescent signal through transcription of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid. 
     
     
         94 . Any one of the preceding claims, wherein transcription levels of the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid range from ten to forty times greater than transcription levels of the luxA nucleic acid and the luxB nucleic acid. 
     
     
         95 . Any one of the preceding claims, wherein transcription levels of the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid range from twenty to thirty times greater than transcription levels of the luxA nucleic acid and the luxB nucleic acid. 
     
     
         96 . Any one of the preceding claims, wherein the nucleic acids encoding each of luxC, luxD, luxE, and flavin reductase are present in a combined level of from ten times to forty times a combined level of nucleic acids encoding luxA and luxB. 
     
     
         97 . Any one of the preceding claims, wherein the nucleic acids encoding each of luxC, luxD, luxE, and flavin reductase are present in a combined level of from twenty times to thirty times a combined level of nucleic acids encoding luxA and luxB. 
     
     
         98 . Any one of the preceding claims, wherein the stem cell or the at least one stem cell further comprises luxA, luxB, luxC, luxD, luxE, and flavin reductase. 
     
     
         99 . Any one of the preceding claims, wherein the stem cell or the at least one stem cell expresses luxA, luxB, luxC, luxD, luxE, and flavin reductase. 
     
     
         100 . Any one of the preceding claims, wherein a combined production level of luxC, luxD, luxE, and flavin reductase ranges from ten to forty times greater than a combined production level of luxA and luxB. 
     
     
         101 . Any one of the preceding claims, wherein a combined production level of luxC, luxD, luxE, and flavin reductase ranges from twenty to thirty times greater than a combined production level of luxA and luxB. 
     
     
         102 . Any one of the preceding claims, wherein at least one of luxC, luxD, luxE, and flavin reductase is present at a level greater than a level of at least one of luxA and luxB. 
     
     
         103 . Any one of the preceding claims, wherein luxC, luxD, luxE, and flavin reductase are present at a combined level of from ten times to forty times greater than a combined level of luxA and luxB. 
     
     
         104 . Any one of the preceding claims, wherein luxC, luxD, luxE, and flavin reductase are present at a combined level of from twenty times to thirty times greater than a combined level of luxA and luxB. 
     
     
         105 . Any one of the preceding claims, wherein the stem cell or the at least one stem cell comprising luxA, luxB, luxC, luxD, luxE, and flavin reductase autonomously luminesces in the absence of an exogenous luminescent stimulator. 
     
     
         106 . Any one of the preceding claims, wherein the constitutive promoter is a chicken beta-actin promoter. 
     
     
         107 . Any one of the preceding claims, wherein the first constitutive promoter and the second constitutive promoter is a chicken beta-actin promoter. 
     
     
         108 . Any one of the preceding claims, wherein at least one of the luxA nucleic acid, the luxB nucleic acid, the luxC nucleic acid, the luxD nucleic acid, the luxE nucleic acid, and the flavin reductase nucleic acid is operatively linked to at least one linker region. 
     
     
         109 . Any one of the preceding claims, wherein the at least one linker region comprises a viral 2A peptide. 
     
     
         110 . Any one of the preceding claims, wherein the agent comprises a chemotherapeutic agent, an antibiotic, an insecticide, a pesticide, an herbicide, or a fertilizer. 
     
     
         111 . Any one of the preceding claims, wherein the stem cell or the at least one stem cell is an induced pluripotent stem cell, a mesenchymal stem cell, or a non-embryonic stem cell. 
     
     
         112 . Any one of the preceding claims, wherein the exogenous luminescent stimulator is a fluorescent stimulation signal. 
     
     
         113 . Any one of the preceding claims, wherein the exogenous luminescent stimulator is a chemical luminescent activator, and preferably wherein the chemical luminescent activator comprises an aldehyde functional group.