title: Differential selection on gene translation efficiency between the filamentous fungus Ashbya gossypii and yeasts.
abstract: BACKGROUND
  The filamentous fungus Ashbya gossypii grows into a multicellular mycelium that is distinct from the unicellular morphology of its closely related yeast species. It has been proposed that genes important for cell cycle regulation play central roles for such phenotypic differences. Because A. gossypii shares an almost identical set of cell cycle genes with the typical yeast Saccharomyces cerevisiae, the differences might occur at the level of orthologous gene regulation. Codon usage patterns were compared to identify orthologous genes with different gene regulation between A. gossypii and nine closely related yeast species.
  
  
  RESULTS
  Here we identified 3,151 orthologous genes between A. gossypii and nine yeast species. Two groups of genes with significant differences in codon usage (gene translation efficiency) were identified between A. gossypii and yeasts. 333 genes (Group I) and 552 genes (Group II) have significantly higher translation efficiency in A. gossypii and yeasts, respectively. Functional enrichment and pathway analysis show that Group I genes are significantly enriched with cell cycle functions whereas Group II genes are biased toward metabolic functions.
  
  
  CONCLUSIONS
  Because translation efficiency of a gene is closely related to its functional importance, the observed functional distributions of orthologous genes with different translation efficiency might account for phenotypic differentiation between A. gossypii and yeast species. The results shed light on the mechanisms for pseudohyphal growth in pathogenic yeast species.
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA. jianghf3@mail.kiz.ac.cn
authors.forename: Huifeng
authors.initials: H
authors.lastname: Jiang
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Zhenglong
authors.initials: Z
authors.lastname: Gu
mesh_terms: D002453:Cell Cycle; D003062:Codon; D055169:Eremothecium / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism; D012641:Selection, Genetic; D015003:Yeasts / Q000235:genetics* / Q000378:metabolism
chemical_list: D003062:Codon; D005656:Fungal Proteins; D012343:RNA, Transfer