Polypeptides, nucleic acids and uses thereof

Abstract

We describe an ELABELA polypeptide comprising a sequence CXXXRCXXXHSRVPFP (SEQ ID NO: 1), in which X signifies an amino acid residue, such as a sequence selected from the group consisting of: SEQ ID NO: 2 to SEQ ID NO: 18, preferably CLQRRCMPLHSRVPFP (SEQ ID NO: 2), or a fragment, homologue, variant or derivative thereof, which polypeptide is capable of maintaining self-renewal and/or pluripotency of a stem cell.

1 . An isolated antibody or antigen-binding fragment thereof that specifically binds to one or more of the following:
 (a) a polypeptide comprising the sequence CMPLHSRVPFP (SEQ ID NO: 52);   (b) a polypeptide comprising the sequence QRPVNLTMRRKLRKHNC (SEQ ID NO: 53);   (c) a polypeptide comprising the sequence QRPVNLTMRRKLRKHNCLQRRCMPLHSRVPFP (SEQ ID NO: 2); and   (d) an ELABELA polypeptide comprising the sequence of any of SEQ ID NOs: 1-36.   
     
     
         2 . The isolated antibody or antigen-binding fragment thereof of  claim 1 , further comprising a label. 
     
     
         3 . An immunoassay kit for measuring or detecting ELABELA expression, the immunoassay kit comprising:
 (a) a coating antigen comprising one or more isolated antibodies or antigen-binding fragments thereof that specifically binds to one or more of the following:
 (i) a polypeptide comprising the sequence CMPLHSRVPFP (SEQ ID NO: 52); 
 (ii) a polypeptide comprising the sequence QRPVNLTMRRKLRKHNC (SEQ ID NO: 53); 
 (iii) a polypeptide comprising the sequence QRPVNLTMRRKLRKHNCLQRRCMPLHSRVPFP (SEQ ID NO: 2); or
 (iv) an ELABELA polypeptide comprising the sequence of any of SEQ ID NOs: 1-36; and 
 
   (b) instructions for using said coating antigen.   
     
     
         4 . The immunoassay kit of  claim 3 , wherein the isolated antibodies or antigen-binding fragments thereof are labelled. 
     
     
         5 . The immunoassay kit of  claim 3 , further comprising an enzyme labelled reagent, a secondary antibody that specifically binds to the isolated antibodies or antigen-binding fragments, a solid substrate, or any combination thereof.