RNA Polymerase II CTD‐Associated DNA Repair and Recombination

We show that a surprisingly large fraction of RNA polymerase II (RNAPII) phosphoCTD‐associating proteins, otherwise falling into diverse functional categories, are required for normal levels of resistance to ionizing radiation and other DNA damaging agents in yeast. Interfering with deployment of this group of proteins to the phosphoCTD of elongating RNAPII causes an increase in sensitivity to DNA damaging agents. Because transcription‐associated recombination also appears to be affected, we refer to proteins in this collection as CTD‐associating repair and recombination (CARR) proteins. We find that disabling the phosphoCTD‐binding ability of even a single CARR protein increases DNA damage sensitivity. For many of the CARR genes, deletion leads to damage‐sensitivity mainly in diploids, suggesting connections between the PCTD of elongating RNAPII and the machinery of homologous recombination in G1. Experiments are in progress to test these connections. We propose that the CTD plus associated CARR proteins comprise a novel genome integrity‐maintenance system.