The mRNA encoding the yeast ARE-binding protein Cth2 is generated by a novel 3' processing pathway.
Microarray analyses of mRNAs over-expressed in strains lacking the nuclear exosome component Rrp6 identified the transcript encoding the ARE-binding protein Cth2, which functions in cytoplasmic mRNA stability. Subsequent northern analyses revealed that exosome mutants accumulate a 3'-extended transcript at the expense of the mature CTH2 mRNA. The 3' ends of the CTH2 mRNA were mapped to a [GU(3-5)](5) repeat, unlike any previously characterized polyadenylation site. CTH2 mRNA accumulation was not inhibited by mutations in 3'-cleavage and polyadenylation factors, Rna14, Rna15 and Pap1, which block accumulation of other mRNAs. The 3'-extended CTH2 pre-mRNA strongly accumulated in strains with mutations in the TRAMP4 polyadenylation complex or the Nrd1/Nab3/Sen1 complex, and contains multiple Nrd1 and Nab3 binding sites. CTH2 carries a consensus ARE element and levels of the pre-mRNA and mRNA were elevated by mutation of the ARE or inactivation of the nuclear 5'-exonuclease Rat1. We propose that CTH2 mRNA is processed from a 3'-extended primary transcript by the exosome, TRAMP and Nrd1/Nab3/Sen1 complexes. This unusual pathway may allow time for nuclear, ARE-mediated regulation of CTH2 levels involving Rat1.
Ciais
Delphine
D
Wellcome Trust Centre for Cell Biology, University of Edinburgh, EH9 3JR, UK.
Bohnsack
Markus T
MT
Tollervey
David
D
D020413:3' Untranslated Regions / Q000737:chemistry; D004265:DNA Helicases; D005656:Fungal Proteins; D015966:Gene Expression Regulation, Fungal; D009687:Nuclear Proteins / Q000378:metabolism; D000073718:Pancreatitis-Associated Proteins; D026723:Polyadenylation; D026721:RNA 3' End Processing; D020365:RNA Helicases; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D038621:Regulatory Sequences, Ribonucleic Acid; D012261:Ribonucleoproteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D051816:Tristetraprolin / Q000235:genetics* / Q000378:metabolism
D020413:3' Untranslated Regions; D005656:Fungal Proteins; C090564:NAB3 protein, S cerevisiae; C491211:NRD1 protein, S cerevisiae; D009687:Nuclear Proteins; D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C091790:TIS11 protein, S cerevisiae; D051816:Tristetraprolin; C542347:SEN1 protein, S cerevisiae; D004265:DNA Helicases; D020365:RNA Helicases