title: Identification of translational regulation target genes during filamentous growth in Saccharomyces cerevisiae: regulatory role of Caf20 and Dhh1.
abstract: The dimorphic transition of yeast to the hyphal form is regulated by the mitogen-activated protein kinase and cyclic AMP-dependent protein kinase A pathways in Saccharomyces cerevisiae. Signaling pathway-responsive transcription factors such as Ste12, Tec1, and Flo8 are known to mediate filamentation-specific transcription. We were interested in investigating the translational regulation of specific mRNAs during the yeast-to-hyphal-form transition. Using polyribosome fractionation and RT-PCR analysis, we identified STE12, GPA2, and CLN1 as translation regulation target genes during filamentous growth. The transcript levels for these genes did not change, but their mRNAs were preferentially associated with polyribosomes during the hyphal transition. The intracellular levels of Ste12, Gpa2, and Cln1 proteins increased under hyphal-growth conditions. The increase in Ste12 protein level was partially blocked by mutations in the CAF20 and DHH1 genes, which encode an eIF4E inhibitor and a decapping activator, respectively. In addition, the caf20 and dhh1 mutations resulted in defects in filamentous growth. The filamentation defects caused by caf20 and dhh1 mutations were suppressed by STE12 overexpression. These results suggest that Caf20 and Dhh1 control yeast filamentation by regulating STE12 translation.
authors.affiliation: Department of Microbiology, School of Bioscience and Biotechnology, Chungnam National University, Yuseong-Gu, Gung-Dong 220, Daejeon 305-764, Republic of Korea.
authors.forename: Young-Un
authors.initials: YU
authors.lastname: Park
authors.forename: Hyangsuk
authors.initials: H
authors.lastname: Hur
authors.forename: Minhan
authors.initials: M
authors.lastname: Ka
authors.forename: Jinmi
authors.initials: J
authors.lastname: Kim
mesh_terms: D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000235:genetics*; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D009154:Mutation; D039502:Nuclear Cap-Binding Protein Complex / Q000235:genetics*; D014176:Protein Biosynthesis; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C082719:CLN1 protein, S cerevisiae; D016213:Cyclins; D044385:GTP-Binding Protein alpha Subunits; D039502:Nuclear Cap-Binding Protein Complex; D012331:RNA, Fungal; D012333:RNA, Messenger; C489241:STE12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C445083:DHH1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; C083907:Gpa2 protein, S cerevisiae