Domainal organization of the lower eukaryotic homologs of the yeast RNA polymerase II core subunit Rpb7 reflects functional conservation

Singh, Sunanda R and Rekha, Nambudiry and Pillai, Beena and Singh, Vijender and Naorem, Aruna and Sampath, Vinaya and Srinivasan, N and Sadhale, Parag (2004) Domainal organization of the lower eukaryotic homologs of the yeast RNA polymerase II core subunit Rpb7 reflects functional conservation. In: Nucleic Acids Research, 32 (1). pp. 201-210.

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Abstract

The subcomplex of Rpb4 and Rpb7 subunits of RNA pol II in Saccharomyces cerevisiae is known to be an important determinant of transcription under a variety of physiological stresses. In S.cerevisiae, RPB7 is essential for cell viability while rpb4 null strains are temperature sensitive at low and high temperatures. The rpb4 null strain also shows defect in sporulation and a predisposed state of pseudohyphal growth. We show here that, apart from S.cerevisiae Rpb7, the Rpb7 homologs from other lower eukaryotes like Schizosaccharomyces pombe, Candida albicans and Dictyostelium discoideum can complement for the absence of S.cerevisiae RPB7. This is the first report where we have shown that both the C.albicans and D.discoideum homologs are functional orthologs of the yeast RPB7. We also show that high expression levels of S.cerevisiae RPB7 and its homologs rescue the sporulation defect of rpb4 homozygous null diploids, but only some of them cause significant enhancement of the pseudohyphal phenotype. Structural modeling of Rpb7 and its homologs show a high degree of conservation in the overall structure. This study indicates a structural and functional conservation of different Rpb7 across species and also a conserved role of Rpb7 in the subcomplex with respect to nutritional stress.

Item Type:	Journal Article
Publication:	Nucleic Acids Research
Publisher:	Oxford University Press
Additional Information:	Copyright of this article belongs to Oxford University Press.
Keywords:	2 Dissociable subunits;Ess1 prolyl isomerase;Saccharomyces-cerevisiae;Temperature extremes;Nonessential subunit;Stress survival;Cell viability;Nucleic-acid;In-vitro;Pol-II
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	18 Dec 2008 12:03
Last Modified:	19 Sep 2010 04:54
URI:	http://eprints.iisc.ac.in/id/eprint/16881

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