Comment

P element transposition and targeted manipulation of the Drosophila genome

A set of molecular genetic technologies are described, which will have far reaching consequences for the study of brain structure, function and development in Drosophila melanogaster. Site selected mutagenesis (a PCR-based screen for P-element insertion events) allows insertion mutants to be isolated for any cloned gene, and is being used in this laboratory to ask questions about the rolls of particular cellular components in learning and memory. Transposants have been isolated in genes encoding a regulatory (RI) and a catalytic (DCO) subunit of cAMP-dependent protein kinase, and in a gene encoding a Gi-like alpha subunit. The alternative use of I factors is described. The PKA RI homozygous mutants display a significant decrement in initial learning ability. Enhancer-trap strategies, for which the GAL-4 P-element system is particularly convenient, allow the identification of genes expressed in the developing fly brain. Strategies for the efficient detection of such events are described.