Characterization of revertants of unc-93(e1500) in Caenorhabditis elegans induced by N-ethyl-N-nitrosourea.
Phenotypic reversion of the rubber-band, muscle-defective phenotype conferred by unc-93(e1500) was used to determine the utility of N-ethyl-N-nitrosourea (ENU) as a mutagen for genetic research in Caenorhabditis elegans. In this system, ENU produces revertants at a frequency of 3 x 10(-4), equivalent to that of the commonly used mutagen, EMS. The gene identity of 154 ENU-induced revertants shows that the distribution of alleles between three possible suppressor genes differs from induced by EMS. A higher percentage of revertants are alleles of unc-93 and many fewer are alleles of sup-9 and sup-10. Three revertants complement the three known suppressor genes; they may therefore identify a new gene product(s) involved in this system of excitation-contraction coupling in C. elegans. Molecular characterization of putative unc-93 null alleles reveals that the base changes induced by ENU are quite different from those induced by EMS; specifically we see an increased frequency of A/T-->G/C transitions. The frequency of ENU-induced intragenic deletions is found to be 13%. We suggest that ENU, at concentrations below 5 mM, will be a superior mutagen for studies of protein function in C. elegans.
De Stasio
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Department of Biology, Lawrence University, Appleton, Wisconsin 54911, USA. elizabeth.a.destasio@lawrence.edu
Lephoto
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C
Azuma
L
L
Holst
C
C
Stanislaus
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D
Uttam
J
J
D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D005038:Ethylnitrosourea / Q000633:toxicity*; D005804:Genes, Lethal; D016153:Genes, Suppressor; D015801:Helminth Proteins / Q000235:genetics*; D008565:Membrane Proteins; D009124:Muscle Proteins / Q000235:genetics*; D009153:Mutagens / Q000633:toxicity*; D017354:Point Mutation; D018807:Polymorphism, Single-Stranded Conformational
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D009153:Mutagens; C073904:unc-93 protein, C elegans; D005038:Ethylnitrosourea