Re. Dodson et Dj. Shapiro, AN ESTROGEN-INDUCIBLE PROTEIN BINDS SPECIFICALLY TO A SEQUENCE IN THE3' UNTRANSLATED REGION OF ESTROGEN-STABILIZED VITELLOGENIN MESSENGER-RNA, Molecular and cellular biology, 14(5), 1994, pp. 3130-3138
The 3' untranslated region (3'-UTR) has been implicated in the estroge
n stabilization of hepatic Xenopus laevis vitellogenin mRNA. We used R
NA gel mobility shift assays to demonstrate that Xenopus liver contain
s 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-affi
nity binding site in the vitellogenin mRNA 3'-UTR and localized the bi
nding site to a 27-nucleotide region. Since binding was abolished by p
roteinase 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 vitel
logenin mRNA-binding protein was found in both polysomes and cytosol.
Since the protein was also estrogen inducible in cytosol, this represe
nts a genuine induction, not simply recruitment of the cytosolic prote
in into polysomes. UV cross-linking studies with the 27-nucleotide rec
ognition sequence revealed bands corresponding to bound proteins with
apparent molecular weights of 71,000 and 141,000. This appears to be t
he first example of steroid hormone-inducible proteins binding to an m
RNA 3'-UTR. Its induction by estrogen and its sequence-specific bindin
g to a region of vitellogenin mRNA important in estrogen-mediated stab
ilization suggest that the protein may play a role in the regulation o
f mRNA stability.