A yeast heterogeneous nuclear ribonucleoprotein complex associated with RNA polymerase II.
Recent evidence suggests a role for the carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II (pol II) in pre-mRNA processing. The yeast NRD1 gene encodes an essential RNA-binding protein that shares homology with mammalian CTD-binding proteins and is thought to regulate mRNA abundance by binding to a specific cis-acting element. The present work demonstrates genetic and physical interactions among Nrd1p, the pol II CTD, Nab3p, and the CTD kinase CTDK-I. Previous studies have shown that Nrd1p associates with the CTD of pol II in yeast two-hybrid assays via its CTD-interaction domain (CID). We show that nrd1 temperature-sensitive alleles are synthetically lethal with truncation of the CTD to 9 or 10 repeats. Nab3p, a yeast hnRNP, is a high-copy suppressor of some nrd1 temperature-sensitive alleles, interacts with Nrd1p in a yeast two-hybrid assay, and coimmunoprecipitates with Nrd1p. Temperature-sensitive alleles of NAB3 are suppressed by deletion of CTK1, a kinase that has been shown to phosphorylate the CTD and increase elongation efficiency in vitro. This set of genetic and physical interactions suggests a role for yeast RNA-binding proteins in transcriptional regulation.
Conrad
N K
NK
Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Wilson
S M
SM
Steinmetz
E J
EJ
Patturajan
M
M
Brow
D A
DA
Swanson
M S
MS
Corden
J L
JL
D000483:Alleles; D001483:Base Sequence; D017931:DNA Primers; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D016153:Genes, Suppressor; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D012319:RNA Polymerase II / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D014158:Transcription, Genetic
D017931:DNA Primers; D005656:Fungal Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C491211:NRD1 protein, S cerevisiae; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D012319:RNA Polymerase II