Polysomal ribonuclease 1 exists in a latent form on polysomes prior to estrogen activation of mRNA decay

Estrogen induces a global change in the translation profile of Xenopus hepatocytes, replacing serum protein synthesis with production of the yolk protein precursor vitellogenin. This is accomplished by the coordinate destabilization of serum protein mRNAs and the transcriptional induction and subseq...

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Bibliographic Details
Published in:Nucleic acids research 2001-03, Vol.29 (5), p.1156-1162
Main Authors: Cunningham, K S, Hanson, M N, Schoenberg, D R
Format: Article
Language:English
Subjects:
Animals
Centrifugation, Density Gradient
Endoribonucleases - metabolism
Enzyme Activation - drug effects
Estrogens - pharmacology
Liver Extracts - metabolism
Male
mRNA decay
PMR1 protein
Polyribosomes - enzymology
polysomal ribonuclease 1
Ribonucleoproteins - metabolism
RNA, Messenger - drug effects
RNA, Messenger - genetics
RNA, Messenger - metabolism
Xenopus
Xenopus laevis - genetics
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Summary:Estrogen induces a global change in the translation profile of Xenopus hepatocytes, replacing serum protein synthesis with production of the yolk protein precursor vitellogenin. This is accomplished by the coordinate destabilization of serum protein mRNAs and the transcriptional induction and subsequent stabilization of vitellogenin mRNA. Previous work identified an endonuclease activity whose appearance on polysomes correlated with the disappearance of serum protein mRNAs. This enzyme, polysomal ribonuclease 1 (PMR1), is a novel member of the peroxidase gene family. The current study examined the association of PMR1 with its mRNA targets on polysomes and mRNPs. The highest amount of polysome-bound PMR1 was observed prior to estrogen induction of mRNA decay. Its distribution on sucrose density gradients matched the absorbance profile of polysome-bound mRNA, suggesting that PMR1 forms a latent complex with mRNA. Following dissociation with EDTA the 62 kDa PMR1 sedimented with a larger complex of >670 kDa. Estrogen induces a 22-fold increase in unit enzymatic activity of polysome-bound PMR1, and a time-dependent loss of PMR1 from polysomes in a manner that mirrors the disappearance of albumin mRNA. These data suggest that the key step in the extensive estrogen-induced change in mRNA decay in Xenopus liver is activation of a latent mRNA endonuclease associated with its target mRNA.
ISSN:1362-4962
0305-1048
1362-4962
DOI:10.1093/nar/29.5.1156