Developmental control elements in the promoter of a Drosophila vitelline membrane gene.

DNA fragments from the 5' flanking region of Drosophila melanogaster vitelline membrane gene VM26A1 were fused to hsp/lacZ reporter genes, reintroduced via P-element-mediated germ line transformation, and functionally assayed by histological staining for beta-galactosidase activity. A developmental control element capable of promoting the basic vitelline membrane (VM) expression pattern was found within a 176-bp region. Additional multiple genetic control elements were found to be involved in modifying the level and spatial pattern of reporter gene expression but these required the 176-bp element in order to function. Unexpectedly, in isolation this 176-bp core element also promotes abnormal expression of the reporter gene in border cells of stage 8 and 9 egg chambers. This abnormal border cell expression is apparently suppressed in the native gene by an adjacent negative control element.