title: Identification and characterization of DdRPB4, a subunit of Dictyostelium discoideum RNA polymerase II.
abstract: Rpb4, the fourth largest subunit of the eukaryotic RNA polymerase II (RNAPII), is required for growth at extreme temperatures and for an appropriate response to nutrient starvation in yeast. Sequence homologs of Rpb4 are found in most sequenced genomes from yeast to humans. To elucidate the role of this subunit in nutrient starvation, we chose Dictyostelium discoideum, a soil amoeba, which responds to nutrient deprivation by undergoing a complex developmental program. Here we report the identification of homolog of Saccharomyces cerevisiae RPB4 in D. discoideum. Localization and complementation studies suggest that Rpb4 is functionally conserved. DdRPB4 transcript and protein levels are developmentally regulated. Although DdRPB4 could not be deleted, overexpression revealed that the Rpb4 protein is essential for cell survival and is regulated stringently at the post-transcriptional level in D. discoideum. Thus maintaining a critical level of Rpb4 is important for this organism.
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, CV Raman Avenue, Bangalore 560012, India.
authors.forename: Aruna
authors.initials: A
authors.lastname: Naorem
authors.forename: Parag P
authors.initials: PP
authors.lastname: Sadhale
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004023:Dictyostelium / Q000201:enzymology*; D005816:Genetic Complementation Test; D018503:Genome, Protozoan; D008969:Molecular Sequence Data; D021122:Protein Subunits; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D021122:Protein Subunits; D015800:Protozoan Proteins; D012319:RNA Polymerase II