The nucleotide excision repair epistasis group in Neurospora crassa

Baker, T. I.; Cords, Carl E.; Howard, C A; Radloff, Roger

doi:10.1007/bf00318382

Cited by 17 publications

(1 citation statement)

References 13 publications

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“…However, later data do not agree with this assignment. (1) Both upr-1 and uvs-2 mutants can excise pyrimidine dimers (Baker et al 1990(Baker et al , 1991. (2) Double mutants carrying the upr-1 and uvs-2 mutations showed slightly higher UV sensitivity than either of the single mutants (Ishii and Inoue 1989).…”

Section: Discussionmentioning

confidence: 99%

The upr-1 gene encodes a catalytic subunit of the DNA polymerase ζ which is involved in damage-induced mutagenesis in Neurospora crassa

2002

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The upr-1 mutant was one of the first mutagen-sensitive mutants to be isolated in Neurospora crassa. However, the function of the upr-1 gene has not yet been elucidated, although some genetic and biochemical data have been accumulated. In order to clone the upr-1 gene, we performed a chromosome walk from the mat locus, the closest genetic marker to upr-1 for which a molecular probe was available, towards the centromere, and a chromosomal contig of about 300-400 kb was constructed. Some of these clones complemented the temperature sensitivity of the un-16 mutation, which is located between mat and upr-1. The un-16 gene was sequenced, and localized in the MIPS Neurospora crassa genome database. We then searched the regions flanking un-16 for homologs of known DNA repair genes, and found a gene homologous to the REV3 gene of budding yeast. The phenotype of the upr-1 mutant is similar to that of the yeast rev3 mutant. An ncrev3 mutant carrying mutations in the N. crassa REV3 homolog was constructed using the RIP (repeat-induced point mutation) process. The spectrum of mutagen sensitivity of the ncrev3 mutant was similar to that of the upr-1 mutant. Complementation tests between the upr-1 and ncrev3 mutations indicated that the upr-1 gene is in fact identical to the ncrev3 gene. To clarify the role of the upr-1 gene in DNA repair, the frequency of MMS and 4NQO-induced mutations was assayed using the ad-8 reversion test. The upr-1 mutant was about 10 times less sensitive to both chemicals than the wild type. The expression level of the upr-1 gene is increased on exposure to UV irradiation in the uvs-2 and mus-8 mutants, which belong to postreplication repair group, as well as in the wild type. All these results suggest that the product of the upr-1 gene functions in damage-induced mutagenesis and DNA translesion synthesis in N. crassa.

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Section: Discussionmentioning

confidence: 99%