The role of the Brr5/Ysh1 C-terminal domain and its homolog Syc1 in mRNA 3'-end processing in Saccharomyces cerevisiae.
The cleavage/polyadenylation factor (CPF) of Saccharomyces cerevisiae is thought to provide the catalytic activities of the mRNA 3'-end processing machinery, which include endonucleolytic cleavage at the poly(A) site, followed by synthesis of an adenosine polymer onto the new 3'-end by the CPF subunit Pap1. Because of similarity to other nucleases in the metallo-beta-lactamase family, the Brr5/Ysh1 subunit has been proposed to be the endonuclease. The C-terminal domain of Brr5 lies outside of beta-lactamase homology, and its function has not been elucidated. We show here that this region of Brr5 is necessary for cell viability and mRNA 3'-end processing. It is highly homologous to another CPF subunit, Syc1. Syc1 is not essential, but its removal improves the growth of other processing mutants at restrictive temperatures and restores in vitro processing activity to cleavage/ polyadenylation-defective brr5-1 extract. Our findings suggest that Syc1, by mimicking the essential Brr5 C-terminus, serves as a negative regulator of mRNA 3'-end formation.
Zhelkovsky
Alexander
A
Department of Molecular Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA.
Tacahashi
Yoko
Y
Nasser
Tommy
T
He
Xiaoyuan
X
Sterzer
Ulrike
U
Jensen
Torben Heick
TH
Domdey
Horst
H
Moore
Claire
C
D000595:Amino Acid Sequence; D017353:Gene Deletion; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D016296:Mutagenesis; D000073718:Pancreatitis-Associated Proteins; D017434:Protein Structure, Tertiary; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D039221:mRNA Cleavage and Polyadenylation Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D012331:RNA, Fungal; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C450401:YSH1 protein, S cerevisiae; D039221:mRNA Cleavage and Polyadenylation Factors