Adjacent GATA and kappaB-like motifs regulate the expression of a Drosophila immune gene.

摘要

The GATA motif is a well known positive cis-regulatory element in vertebrates. In this work, experimental evidence for the direct participation of a GATA motif in the expression of the Drosophila antibacterial peptide gene Cecropin A1 is reported. Previously it has been shown that a kappaB-like site is necessary for Cecropin A1 gene expression. Here evidence is presented that the Drosophila Rel protein which binds to the kappaB-like site requires an intact GATA site for maximal Dif-mediated transactivation of the Cecropin A1 gene. It is shown that a Drosophila blood cell line contains factors binding specifically to the GATA motif of the Cecropin A1 gene. The GATA binding activity is likely to include member(s) of the GATA family of transcriptional regulators. It is shown that the promoters of several inducible insect immune genes possess GATA sites 0-12 base pairs away from kappaB-like sites in functionally important promoter regions. Clusters of GATA and kappaB sites are also observed in the promoters of 2 important mammalian immune genes, namely IL6 and IL3. The consistent proximity of GATA and kappaB sites appears to be a common theme in the immune gene expression of insects and mammals.