Phenotypic and epistatic grouping of hypo- and hyper-rec mus mutants in Aspergillus

Curr Genet. 1994 Mar;25(3):223-32. doi: 10.1007/BF00357166.


The mutants musK to musS of Aspergillus nidulans are sensitive to methyl-methanesulfonate (MMS) and several of them are meiotic-defective and alter mitotic recombination frequencies. All were found to be cross-sensitive to 4-nitro-quinoline-N-oxide (4-NQO) but unexpectedly none of them was hypersensitive to gamma-rays and few to UV light. Double mus; uvs mutants were constructed to test for interactions with uvs mutations of the four epistatic groups of Aspergillus, "UvsF", "UvsC", "UvsI", and "UvsB". All meiotic-defective mus mutations caused some lethal interactions, usually with uvsF. None of them showed epistasis with UvsF or UvsB group mutants and one, musO, may represent a new group. Three mus mutations that affect recombination were assigned to the UvsC group, namely musN and K, and also musL which is recombination-defective and closely resembles uvsC. While uvsC mutants are mutators and lack UV-mutagenesis, most mus mutants had no effects on mutation. Only musR, which appeared epistatic with uvsI, showed reduced UV-reversion frequencies similar to uvsI. The recombination-proficient mus mutants appeared to be epistatic with more than one group, but in several cases sensitivities were slight and overlaps insufficient to obtain corroborating results with MMS and 4-NQO.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Nitroquinoline-1-oxide / pharmacology
  • Aspergillus nidulans / drug effects
  • Aspergillus nidulans / genetics*
  • Aspergillus nidulans / radiation effects
  • DNA Repair / genetics
  • DNA, Fungal / drug effects
  • DNA, Fungal / genetics
  • DNA, Fungal / radiation effects
  • Drug Resistance, Microbial / genetics
  • Epistasis, Genetic*
  • Gamma Rays
  • Genes, Fungal*
  • Meiosis / genetics
  • Methyl Methanesulfonate / pharmacology
  • Mutagenesis
  • Phenotype
  • Radiation Tolerance / genetics
  • Recombination, Genetic*
  • Ultraviolet Rays


  • DNA, Fungal
  • 4-Nitroquinoline-1-oxide
  • Methyl Methanesulfonate