An estrogen-inducible protein binds specifically to a sequence in the 3' untranslated region of estrogen-stabilized vitellogenin mRNA.
The 3' untranslated region (3'-UTR) has been implicated in the estrogen stabilization of hepatic Xenopus laevis vitellogenin mRNA. We used RNA gel mobility shift assays to demonstrate that Xenopus liver contains a factor which binds with very high specificity to a segment of the 3'-UTR of vitellogenin B1 and B2 mRNAs. We detected a single high-affinity binding site in the vitellogenin mRNA 3'-UTR and localized the binding site to a 27-nucleotide region. Since binding was abolished by proteinase K digestion, at least a component of the factor is a protein. Following estrogen administration, binding was induced approximately four- to fivefold in extracts from liver polysomes. The hepatic vitellogenin mRNA-binding protein was found in both polysomes and cytosol. Since the protein was also estrogen inducible in cytosol, this represents a genuine induction, not simply recruitment of the cytosolic protein into polysomes. UV cross-linking studies with the 27-nucleotide recognition sequence revealed bands corresponding to bound proteins with apparent molecular weights of 71,000 and 141,000. This appears to be the first example of steroid hormone-inducible proteins binding to an mRNA 3'-UTR. Its induction by estrogen and its sequence-specific binding to a region of vitellogenin mRNA important in estrogen-mediated stabilization suggest that the protein may play a role in the regulation of mRNA stability.
Dodson
R E
RE
Department of Biochemistry, University of Illinois, Urbana 61801.
Shapiro
D J
DJ
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003600:Cytosol / Q000378:metabolism; D019286:Endopeptidase K; D004967:Estrogens / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010957:Plasmids; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D015183:Restriction Mapping; D012697:Serine Endopeptidases; D014819:Vitellogenins / Q000096:biosynthesis*; D014982:Xenopus laevis
D004967:Estrogens; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014819:Vitellogenins; D012697:Serine Endopeptidases; D019286:Endopeptidase K