Reductions of spontaneous and UV-induced reversion of certain mutant alleles have been shown in uvsl mutant strains of Aspergillus nidulans. To facilitate cloning of the uvsl gene on MMS containing plates, uvsl, uvsA double mutants exhibiting very high MMS-sensitivity were used as a transformation host, since either single mutant was no more than slightly sensitive to MMS. An uvsl-complementing clone was obtained from a chromosome III specific library. Sequence determination of a minimally localized DNA fragment having the uvsl-complementing activity within the clone revealed an ORF with the highest amino acid identity to yeast REV3, a subunit of the DNA polymerase zeta involved in translesion DNA synthesis. UV-survival of heterozygous diploids of uvs1501 with a disruptant of the cloned gene demonstrating the same UV-survival curve as that for homozygous uvsI501 diploids confirmed that the cloned gene is the uvsl. The uvs/ORF encodes a polypeptide of 1,681 amino acids with calculated MW of 191.4 KDa. One small intron of 54 by at near the N-terminus is confirmed by sequencing of RT-PCR products. A Northern blot band of about 5.3 kb was detected. In UVSI, the well- conserved regions, I-VI, among DNA polymerases were present in the correct order. In addition, two zinc-finger motives, [C-X2-CJ-X11-[C-X2-C] and [C-X2-CJ-X10-[C-X4-CJ, existed similarly to REV3. Further sequencing of an upstream region of uvsl revealed another ORF of 1,401 by without putative intron. This ORF resides very close to uvsl in opposite direction and encodes a putative polypeptide exhibiting high amino acid similarity to two hypothetical Arabidopsis proteins. A possible relationship between uvsl and the ORF is currently being carried out.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)