Chimeric human CstF-77/Drosophila Suppressor of forked proteins rescue suppressor of forked mutant lethality and mRNA 3′ end processing in Drosophila
- Génétique du Développement de la Drosophile, Institut de Génétique Humaine, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France
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Edited by Michael S. Levine, University of California, Berkeley, CA, and approved June 13, 2002 (received for review April 2, 2002)
Abstract
The Suppressor of forked [Su(f)] protein is the Drosophila homologue of CstF-77, a subunit of human cleavage stimulation factor (CstF) that is required for the first step of the mRNA 3′ end processing reaction in vitro. We have addressed directly the role of su(f) in the mRNA 3′ end processing reaction in vivo. We show that su(f) is required for the cleavage of pre-mRNA during mRNA 3′ end formation. Analysis of the functional complementation between Su(f) and CstF-77 shows that most of the Drosophila protein (85%) can be exchanged for the human protein to produce chimeric CstF-77/Su(f) proteins that rescue lethality and cleavage defect during mRNA 3′ end formation in su(f) mutants. Interestingly, we show that a domain in human CstF-77 is limiting for the rescue and that this domain is not able to reproduce protein interactions with the CstF subunits of Drosophila. We also show that chimeric CstF-77/Su(f) proteins that rescue lethality of su(f) mutants cannot restore utilization of a regulated poly(A) site in Drosophila. Taken together, these results demonstrate that CstF-77 and Su(f) have the same function in mRNA 3′ end formation in vivo, but that these two proteins are not interchangeable for regulation of poly(A) site utilization.
Footnotes
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↵ * Present address: Cycle et Détermination Cellulaire, Unité Mixte de Recherche 7622, Bât C, Boite 24, 9 Quai St Bernard, 75252 Paris Cedex 5, France.
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↵ † To whom reprint requests should be addressed. E-mail: Martine.Simonelig{at}igh.cnrs.fr.
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This paper was submitted directly (Track II) to the PNAS office.
- Abbreviations:
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Su(f), Suppressor of forked
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CstF, cleavage stimulation factor
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CPSF, cleavage and polyadenylation specificity factor
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CF, cleavage factor
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GST, glutathione S-transferase
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RT-PCR, reverse transcription–PCR
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- Copyright © 2002, The National Academy of Sciences
