Sequential expression in the nervous system of c-myb and VIP genes, located in human chromosomal region 6q24

Vasoactive intestinal peptide (VIP) is a major neuropeptide involved in multiple functions such as vasodilation, smooth-muscle relaxation, sweat secretion, gastrointestinal peristalsis, pancreatic function, and brain activity. In view of the multiple roles associated with VIP, it is important to understand its gene regulation. We have recently isolated the human VIP gene and determined its structure. By in situ hybridization techniques we have now localized this gene to the long arm of chromosome 6, 6q24, a chromosomal region that has been shown previously to contain the coding sequences for the nuclear protooncogene c-myb. Genes found in close proximity to each other on the chromosome are often functionally related and, as VIP is primarily expressed in the nervous system, we investigated the possible correlation of c-myb to VIP in neuronal tissue. A sharp peak of c-myb mRNA was observed in the hippocampus of 3-day-old rats, preceding the peak of VIP mRNA that occurs in this brain area at 8 days of age. Thus, the protooncogene c-myb may be associated with events in brain development occurring prior to the appearance of elevated concentrations of VIP.