9522307 Federoff, Howard The study of the structure and function of the central nervous system is frequently best elucidated by overproduction or underproduction of the neurochemicals involved in normal neural function. However, at present, there are no molecular mechanisms to control the expression of the genes encoding these chemicals at different sites within the brain or at different times during or after development of the brain. Conventional approaches to over- or underexpress these genes have significant limitations, the worst outcome is the loss of function mutation causing embryonic lethality. The present proposal outlines an innovative mechanism to specifically over- or under expression genes in the central nervous system at specific times and in specific places. These studies will employ the cre-loxP system to generate genetic mosaics. cre is an enzyme recognizing specific DNA sequences (loxP) and initiating recombination at these sites. Specific transgenes are designed incorporating loxP sites in their structure in advance of a DNA expression cassette. After incorporation into the genome organisms are exposed to genetically engineered herpes simplex viruses containing the cre gene. Upon infection cre is expressed, inititing recombination at available loxP sites and over- or underexpression of the targeted DNA cassette. This proposal is appropriate for a SGER award because the studies are innovative and highly risky. These studies, if successful, give this investigator the potential to control the expression of genes in virtually any tissue at any time and could lead to major advances in our understanding of basic brain mechanisms, having direct implications for health and disease.
