Rpb4, a non-essential subunit of core RNA polymerase II of Saccharomyces cerevisiae is important for activated transcription of a subset of genes.

Pillai, Beena and Sampath, Vinaya and Sharma, Nimisha and Sadhale, Parag (2001) Rpb4, a non-essential subunit of core RNA polymerase II of Saccharomyces cerevisiae is important for activated transcription of a subset of genes. In: Journal of Biological Chemistry, 276 (33). pp. 30641-30647.

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Abstract

A major role in regulation of eukaryotic protein coding genes is played by the gene specific transcriptional regulators which recruit the RNA Polymerase II holoenzyme to the specific promoter. Several components of the mediator complex within the holoenzyme also have been shown to affect activation of different subsets of genes. Only recently has it been suggested that besides the largest subunit of RNA polymerase II, smaller subunits like Rpb3 and Rpb5 may have regulatory roles in expression of specific sets of genes. We report here, the role of Rpb4, a non-essential subunit of core RNA polymerase II, in activation of a subset of genes in Saccharomyces cerevisiae. We have shown below, that while constitutive transcription is largely unaffected, activation from various promoters tested is severely compromised in the absence of RPB4. This activation defect can be rescued by the overexpression of cognate activators. We have localised the region of Rpb4 involved in activation to the C-terminal 24 amino acids. We have also shown here that transcriptional activation by artificial recruitment of TBP to the promoter is also defective in the absence of RPB4. Surprisingly, the overexpression of RPB7-the interacting partner of Rpb4 does not rescue the activation defect of all the promoters tested, although it rescues the activation defect of heat shock element containing promoter and the temperature sensitivity associated with RPB4 deletion. Overall, our results imply that Rpb4 and Rpb7 play independent roles in transcriptional regulation of genes.

Item Type:	Journal Article
Publication:	Journal of Biological Chemistry
Publisher:	American Society for Biochemistry and Molecular Biology
Additional Information:	Copyright of this article belongs to American Society for Biochemistry and Molecular Biology.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	15 Oct 2007
Last Modified:	19 Sep 2010 04:39
URI:	http://eprints.iisc.ac.in/id/eprint/12002

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