Endonucleolytic cleavage of pre-mRNAs is the first step during eukaryotic mRNA 3' end formation. It has been proposed that cleavage factors CF IA, CF IB and CF II are required for pre-mRNA 3' end cleavage in yeast. CF IB is composed of a single polypeptide, Nab4p/Hrp1p, which is related to the A/B group of metazoan heterogeneous nuclear ribonucleoproteins (hnRNPs) that function as antagonistic regulators of 5' splice site selection. Here, we provide evidence that Nab4p/Hrp1p is not required for pre-mRNA 3' end endonucleolytic cleavage. We show that CF IA and CF II devoid of Nab4p/Hrp1p are sufficient to cleave a variety of RNA substrates but that cleavage occurs at multiple sites. Addition of Nab4p/Hrp1p prevents these alternative cleavages in a concentration-dependent manner, suggesting an essential and conserved role for some hnRNPs in pre-mRNA cleavage site selection.

• PMID: 9857200
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Reference Type

Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, P.H.S.

Authors

Minvielle-Sebastia L, Beyer K, Krecic AM, Hector RE, Swanson MS, Keller W

Primary Lit For

mRNA cleavage factor complex CFIA

Additional Lit For

CYC1 | HRP1 | hrp1-L205S | hrp1-(nab4-1)

Review For