ISOLATION OF MUTATIONS IN THE DROSOPHILA HOMOLOGS OF THE HUMAN NEUROFIBROMATOSIS-2 AND YEAST CDC42 GENES USING A SIMPLE AND EFFICIENT REVERSE-GENETIC METHOD

Reverse genetic analysis in Drosophila has been greatly aided by a gro wing collection of lethal P transposable element insertions that provi de molecular tags for the identification of essential genetic loci. Ho wever, because the screens performed to date primarily have generated autosomal P-element insertions, this collection has not been as useful for performing reverse genetic analysis of X-linked genes. We have de signed a reverse genetic screen that takes advantage of the hemizygosi ty of the X chromosome in males together with a cosmid-based transgene that serves as an autosomally linked duplication of a small region of the X chromosome. The efficacy and efficiency of this method is demon strated by the isolation of mutations in Drosophila homologues of two well-studied genes, the human Neurofibromatosis 2 tumor suppressor and the yeast CDC42 gene. The method we describe should be of general uti lity for the isolation of mutations in other X-linked genes, and shoul d also provide an efficient method for the isolation of new alleles of existing X-linked or autosomal mutations in Drosophila.