Vigilin binding selectively inhibits cleavage of the vitellogenin mRNA 3′-untranslated region by the mRNA endonuclease polysomal ribonuclease 1

• Published in: Proceedings of the National Academy of Sciences - PNAS 2000-11, Vol.97 (23), p.12498-12502
• Main Authors: Cunningham, K S, Dodson, R E, Nagel, M A, Shapiro, D J, Schoenberg, D R
• Format: Article
• Language: English
• Subjects: 3' Untranslated Regions - chemistry; 3' Untranslated Regions - metabolism; Animals; Base Sequence; Biochemistry; Biological Sciences; Carrier Proteins; Cell Line; Endoribonucleases - metabolism; Humans; Male; Molecular Sequence Data; Nucleic Acid Conformation; PMR-1 protein; Proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Ribonucleic acid; RNA; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Spodoptera - cytology; Substrate Specificity; Vigilin; vitellogenin; Vitellogenins - genetics; Xenopus
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.220425497

In Xenopus , estrogen induces the stabilization of vitellogenin mRNA and the destabilization of albumin mRNA. These processes correlate with increased polysomal activity of a sequence-selective mRNA endonuclease, PMR-1, and a hnRNP K homology-domain RNA-binding protein, vigilin. Vigilin binds to a region of the vitellogenin mRNA 3′-untranslated region (3′-UTR) implicated in estrogen-mediated stabilization. The vigilin-binding site in the vitellogenin B1 mRNA 3′-UTR contains two consensus PMR-1 cleavage sites. The availability of purified PMR-1 and recombinant vigilin made it possible to test the hypothesis that RNA-binding proteins interact with cis-acting elements to stabilize target mRNAs by blocking cleavage by site-specific mRNA endonucleases. Vigilin binds to the vitellogenin mRNA 3′-UTR site with at least 30-fold higher affinity than it exhibits for the albumin mRNA segment containing the mapped PMR-1 cleavage sites. This differential binding affinity correlates with differential in vitro susceptibility of the protein–RNA complexes to cleavage by PMR-1. Whereas recombinant vigilin has no detectable protective effect on PMR-1 cleavage of albumin mRNA, it retards in vitro cleavage of the vitellogenin mRNA 3′-UTR by purified PMR-1. The PMR-1 sites in the vitellogenin mRNA 3′-UTR are functional because they are readily cleaved in vitro by purified PMR-1. These results provide direct evidence for differential susceptibility to endonuclease-mediated mRNA decay resulting from the differential affinity of a RNA-binding protein for cis-acting stability determinants.