Compositions and methods for reproducing and modulating mammalian messenger RNA decapping

Abstract

An in-vitro system in which mammalian messenger RNA decapping occurs is provided, for use in identifying modulators, deficiencies, and other aspects of the regulation of RNA turnover.

1 - 13 . (canceled)  
     
     
         14 . A polypeptide which has a molecular weight of about 50 to about 100 kilodaltons (kD) in molecular exclusion chromatography, precipitates with 20% ammonium sulfate, elutes at between about 440 to 500 mM NaCl from a heparin-Sepharose column, and decaps mammalian RNA.  
     
     
         15 . A polynucleotide which encodes a polypeptide which has a molecular weight of about 50 to about 100 kilodaltons (kD) in molecular exclusion chromatography, precipitates with 20% ammonium sulfate, elutes at between about 440 to 500 mM NaCl from a heparin-Sepharose column, and decaps mammalian RNA.  
     
     
         16 . An antibody which binds specifically and with high affinity to a polypeptide which has a molecular weight of about 50 to about 100 kilodaltons (kD) in molecular exclusion chromatography, precipitates with 20% ammonium sulfate, elutes at between about 440 to 500 mM NaCl from a heparin-Sepharose column, and decaps mammalian RNA.  
     
     
         17 - 21 . (canceled)  
     
     
         22 . A method for carrying out in vitro mammalian mRNA decapping comprising the steps of: 
 a) providing the composition of claim  1 ,    b) incubating said composition at about 30° C. for about 30 min. and monitoring decapping by detection of release of label from said cap-labeled RNA.    
     
     
         23 . A method for identifying a compound as a modulator of mammalian mRNA decapping comprising carrying out the method of  claim 22  in the presence and absence of said compound, and correlating any change in decapping by the presence of said compound with modulator activity of said compound.  
     
     
         24 . The method of  claim 23  wherein said cap-labeled mRNA substrate comprises poly(A) or at least one RNA element.  
     
     
         25 . The composition of  claim 23  wherein said RNA element is an AU-rich element.  
     
     
         26 . The composition of  claim 23  wherein said RNA element is a pyrimidine-rich element.