Genetics, Vol. 155, 261-272, May 2000, Copyright © 2000
Analysis of Chromosomal Rearrangements Induced by Postmeiotic Mutagenesis With Ethylnitrosourea in Zebrafish
Yoshiyuki Imaia,
Benjamin Feldmanb,
Alexander F. Schierb, and
William S. Talbota
a Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, Stanford, California 94305-5329
b Developmental Genetics Program, Skirball Institute, New York University School of Medicine, New York, New York 10016
Corresponding author:
William S. Talbot, Department of Developmental Biology, Beckman Ctr. B300, Stanford University School of Medicine, 279 Campus Dr., Stanford, CA 94305-5329., talbot{at}cmgm.stanford.edu (E-mail)
Communicating editor: N. A. JENKINS
Mutations identified in zebrafish genetic screens allow the dissection of a wide array of problems in vertebrate biology. Most screens have examined mutations induced by treatment of spermatogonial (premeiotic) cells with the chemical mutagen N-ethyl-N-nitrosourea (ENU). Treatment of postmeiotic gametes with ENU induces specific-locus mutations at a higher rate than premeiotic regimens, suggesting that postmeiotic mutagenesis protocols could be useful in some screening strategies. Whereas there is extensive evidence that ENU induces point mutations in premeiotic cells, the range of mutations induced in postmeiotic zebrafish germ cells has been less thoroughly characterized. Here we report the identification and analysis of five mutations induced by postmeiotic ENU treatment. One mutation, snhst1, is a translocation involving linkage group (LG) 11 and LG 14. The other four mutations, oepst2, knyst3, Df(LG 13)st4, and cycst5, are deletions, ranging in size from less than 3 cM to greater than 20 cM. These results show that germ cell stage is an important determinant of the type of mutations induced. The induction of chromosomal rearrangements may account for the elevated frequency of specific-locus mutations observed after treatment of postmeiotic gametes with ENU.
