YRA1, an essential Saccharomyces cerevisiae gene, encodes a novel nuclear protein with RNA annealing activity

• Published in: RNA (Cambridge) Vol. 3; no. 5; pp. 527 - 537
• Main Authors: Portman, D S, O'Connor, J P, Dreyfuss, G
• Format: Journal Article
• Language: English
• Published: United States 01.05.1997
• Subjects: Amino Acid Sequence; Base Sequence; Cloning, Molecular; Fungal Proteins - biosynthesis; Fungal Proteins - chemistry; Fungal Proteins - genetics; Genes, Fungal; Molecular Sequence Data; Mutagenesis, Site-Directed; Nuclear Proteins - biosynthesis; Nuclear Proteins - chemistry; Nuclear Proteins - genetics; Oligodeoxyribonucleotides; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Ribonucleoproteins - chemistry; RNA Processing, Post-Transcriptional; RNA, Messenger - metabolism; RNA-Binding Proteins; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; Sequence Deletion; Sequence Homology, Amino Acid
• ISSN: 1355-8382; 1469-9001

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.