Nab2p Is Required for Poly(A) RNA Export in Saccharomyces cerevisiae and Is Regulated by Arginine Methylation via Hmt1p

• Published in: The Journal of biological chemistry Vol. 277; no. 10; pp. 7752 - 7760
• Main Authors: Green, Deanna M., Marfatia, Kavita A., Crafton, Emily B., Zhang, Xing, Cheng, Xiaodong, Corbett, Anita H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 08.03.2002; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Arginine - chemistry; Arginine - metabolism; ATP-Binding Cassette Transporters - metabolism; Cell Nucleus - metabolism; Escherichia coli - metabolism; Fluorescent Antibody Technique, Indirect; Fungal Proteins - metabolism; Fungal Proteins - physiology; Gene Deletion; Green Fluorescent Proteins; Hmt1 protein; HnRNP protein; HnRNP proteins; Immunoblotting; In Situ Hybridization, Fluorescence; Luminescent Proteins - metabolism; Methylation; Molecular Sequence Data; Nab2 protein; Nucleocytoplasmic Transport Proteins; Plasmids - metabolism; Poly A - metabolism; Precipitin Tests; Protein Binding; Protein Biosynthesis; Protein Transport; Protein-Arginine N-Methyltransferases; Recombinant Fusion Proteins - metabolism; Repressor Proteins; RNA - metabolism; RNA Polymerase II - metabolism; RNA, Messenger - metabolism; RNA-Binding Proteins - metabolism; RNA-Binding Proteins - physiology; Saccharomyces cerevisiae; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; Temperature; Transcription, Genetic
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M110053200

From transcription to translation, mRNA is complexed with heterogeneous nuclear ribonucleoproteins (hnRNP proteins) that mediate mRNA processing, export from the nucleus, and delivery into the cytoplasm. Although the mechanism is unknown, export of mature mRNA from the nucleus is a critical regulatory step in gene expression. Analyses of hnRNP proteins have shown that many of these proteins are required for this essential cellular process. In this study, we characterize the Saccharomyces cerevisiae Nab2 protein, which was first identified as a poly(A) RNA-binding protein (Anderson, J. T., Wilson, S. M., Datar, K. V., and Swanson, M. S. (1993) Mol. Cell. Biol.13, 2730–2741). Our work indicates that poly(A) RNA export from the nucleus is dependent upon a functional Nab2 protein; correspondingly, export of Nab2p from the nucleus is dependent upon ongoing RNA polymerase II transcription. Furthermore, we show that Nab2p is modified within its RGG domain by the type I protein-arginine methyltransferase, Hmt1p. Our experiments demonstrate that arginine methylation is required for the export of Nab2p from the nucleus and therefore establish an in vivo effect of this modification. Overall, these experiments provide evidence that Nab2p is an hnRNP protein that is required for poly(A) RNA export and whose export from the nucleus is regulated by Hmt1p.