title: RAM pathway contributes to Rpb4 dependent pseudohyphal differentiation in Saccharomyces cerevisiae.
abstract: Rpb4, a subunit of RNA Polymerase II plays an important role in various stress responses in budding yeast, Saccharomyces cerevisiae. In response to nitrogen starvation, diploid yeast undergoes a dimorphic transition to filamentous pseudohyphal growth, which is regulated through cAMP-PKA and MAP kinase pathway. In the present study, we show that disruption of Rpb4 leads to enhanced pseudohyphal growth, which is independent of nutritional status. We observed that the rpb4Delta/rpb4Delta cells exhibit pseudohyphae even in the absence of functional MAP kinase and cAMP-PKA pathways. Genome-wide expression profiling showed that in the absence of Rpb4 several genes controlling mother daughter cell separation are down regulated. Our genetic studies also provide evidence for involvement of RNA Pol II subunit Rpb4 in the expression of genes downstream of the RAM pathway. Finally, we show that this effect on expression of RAM pathway may at least be partially responsible for the pseudohyphal phenotype of rpb4Delta/rpb4Delta cells.
authors.affiliation: Department of Microbiology and Cell biology, Indian Institute of Science, CV Raman Avenue, Bangalore 560 012, India.
authors.forename: Jiyoti
authors.initials: J
authors.lastname: Verma-Gaur
authors.forename: Swati
authors.initials: S
authors.lastname: Deshpande
authors.forename: Parag P
authors.initials: PP
authors.lastname: Sadhale
mesh_terms: D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D025301:Hyphae / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C066778:ACE2 protein, S cerevisiae; D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D017868:Cyclic AMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D012319:RNA Polymerase II; C423309:RPB4 protein, S cerevisiae