title: YRA1, an essential Saccharomyces cerevisiae gene, encodes a novel nuclear protein with RNA annealing activity.
abstract: The complexity of eukaryotic mRNA processing suggests a need for certain factors, called RNA chaperones, that can modulate RNA secondary structure as well as the interactions between pre-mRNA and trans-acting components. To identify factors that may fulfill this role in the yeast Saccharomyces cerevisiae, we fractionated whole-cell extracts and assayed for activity that could facilitate a specific RNA-RNA annealing reaction. We detected one strong RNA annealing activity and purified it to homogeneity. This previously undescribed factor, Yra1p, is localized to the nucleus; its sequence contains one RNP-motif RNA-binding domain. The YRA1 gene contains a 766-nt intron, the second-largest identified in this organism, and Yra1p serves an essential, nonredundant function. Taken together, our findings indicate that Yra1p is likely to have an important role in S. cerevisiae nuclear pre-mRNA metabolism.
authors.affiliation: Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6148, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Portman
authors.forename: J P
authors.initials: JP
authors.lastname: O'Connor
authors.forename: G
authors.initials: G
authors.lastname: Dreyfuss
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D009838:Oligodeoxyribonucleotides; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012261:Ribonucleoproteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
chemical_list: D005656:Fungal Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C105887:YRA1 protein, S cerevisiae