Distinct roles for Khd1p in the localization and expression of bud-localized mRNAs in yeast.
The RNA-binding protein Khd1p (KH-domain protein 1) is required for efficient localization of ASH1 mRNA to the bud-tip, probably acting as a translational repressor during mRNA transport in yeast. Here, we have systematically examined Khd1p mRNA targets and colocalization with known bud-tip-localized mRNAs in vivo. Affinity purification and DNA microarray analysis of Khd1p-associated mRNAs revealed hundreds of potential mRNAs targets, many of them encoding membrane-associated proteins. The putative targets include the messages for MID2, MTL1, WSC2, SRL1, EGT2, CLB2, ASH1, and Khd1p colocalizes with these mRNAs at the bud-tip. The combination of bioinformatics, RNA localization, and in vitro RNA-binding assays revealed that Khd1p binds to CNN repeats in coding regions of mRNA targets. Among the proteins encoded by previously known bud-tip-localized mRNAs, only Mtl1p levels were decreased in khd1Delta mutant cells, whereas Ash1p and Srl1p were reduced in cells overexpressing KHD1. Hence, Khd1p differentially affects gene expression possibly due to combinatorial arrangement with additional factors reflecting the redundant structure of post-transcriptional regulatory systems.
Hasegawa
Yuko
Y
Department of Molecular Cell Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 305-8575 Tsukuba, Japan.
Irie
Kenji
K
Gerber
André P
AP
D000595:Amino Acid Sequence; D002135:Calcium-Binding Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012331:RNA, Fungal / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics; D012261:Ribonucleoproteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
C098733:ASH1 protein, S cerevisiae; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; C443676:HEK2 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; C091625:MID2 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins