Novel roles for elongin C in yeast.

Mammalian Elongin C is a 112-amino acid protein that binds to the von Hippel-Lindau (VHL) tumor suppressor and to Elongin A, the transcriptionally active subunit of the RNA polymerase II elongation factor, SIII. It is conserved in eukaryotic cells, as homologs have been identified in Saccharomyces cerevisiae, Drosophila melanogaster and Caenorhabditis elegans. The mammalian protein is thought to function as part of a ubiquitin targeting E3 ligase, yet the function in yeast has not been determined. In this report we examine the role of Elongin C in yeast and establish that yeast Elongin C may function in a mode distinct from its role as an E3 ligase. The RNA is expressed ubiquitously, albeit at low levels. Two hybrid analyses demonstrate that Elongin C in yeast interacts with a specific set of proteins that are involved in the stress response. This suggests a novel role for Elongin C and provides insights into additional potential functions in mammalian cells.