MOLECULAR-CLONING OF DNAS ENCODING THE REGULATORY SUBUNITS OF ELONGINFROM SACCHAROMYCES-CEREVISIAE AND DROSOPHILA-MELANOGASTER

The Elongin complex strongly stimulates the rate of elongation by RNA polymerase II by suppressing transient pausing by polymerase at many s ites along the DNA. Elongin is composed of a transcriptionally active A subunit and two positive regulatory B and C subunits. The Elongin co mplex is a potential target for regulation by the von Hippel-Lindau (V HL) tumor suppressor protein, which is capable of binding stably to th e Elongin BC complex and preventing it hom activating Elongin A. Here, we report the molecular cloning of a Saccharomyces cerevisiae genomic DNA encoding Elongin C subunit and of Drosophila cDNAs encoding Elong in B and C subunits. The predicted amino acid sequence of each protein shows a high degree of similarity with the mammalian proteins. The re combinant yeast Elongin C protein interacts with both mammalian Elongi n A and VHL tumor suppressor protein. Moreover, yeast Elongin C strong ly induces the transcriptional elongation activity of mammalian Elongi n A. The expression of yeast Elongin C mRNA is dramatically upregulate d during sporulation; however, the gene is not essential for sporulati on and viability in yeast cell. (C) 1997 Academic Press.