THE UVSI GENE OF ASPERGILLUS-NIDULANS REQUIRED FOR UV-MUTAGENESIS ENCODES A HOMOLOG TO REV3, A SUBUNIT OF THE DNA-POLYMERASE-ZETA OF YEAST INVOLVED IN TRANSLESION DNA-SYNTHESIS

Defects in the uvsI gene of Aspergillus nidulans resulted in high UV s ensitivity and reductions of spontaneous and UV-induced reversion of c ertain alleles. uvsI, uvsA double mutants exhibited high methyl methan e sulfonate (MMS)-sensitivity in contrast to the slight sensitivity of the component single mutants. Using such a double mutant as recipient , a clone complementing uvsI501 has been isolated from a chromosome II I specific library. The deduced amino acid sequence from the 1.1-kb se quenced region, a part of the 5.2-kb DNA fragment showing Ill;sl-compl ementing activity, had a 62% identity with REV3 of yeast. Disruptants of the cloned gene demonstrated the same level of sensitivity to UV li ght as uvsI and failed to complement uvsI501 in heterozygous diploids. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.