Identification of a novel bursicon-regulated transcriptional regulator, md13379, in the house fly Musca domestica.

Bursicon is a neuropeptide that regulates cuticle sclerotization (hardening and tanning) and wing expansion in insects via a G-protein coupled receptor. The hormone consists of alpha and beta subunits. In the present study, we cloned bursicon alpha and beta genes in the house fly Musca domestica using 3' and 5' RACE and expressed the recombinant bursicon (rbursicon) heterodimer in mammalian 293 cells and insect Highfive(TM) cells. The rbursicon displayed a strong bursicon activity in the neck-ligated house fly assay. Using rbursicon, we identified and cloned a novel bursicon-regulated gene in M. domestica encoding a transcriptional regulator homologous to ataxin-7-like3 in human, CG13379 in Drosophila and sgf11 in yeast Saccharomyces cerevisiae. We named the gene md13379. Both ataxin-7-like3 and sgf11 are a novel subunit of the SAGA (Spt-Ada-Gcn5-Acetyltransferase) complex that is involved in regulation of gene transcription. Real-time PCR analysis of temporal response profile revealed that the level of md13379 transcript was up-regulated by 6.6 fold 1 h after rbursicon injection, which correlates well with the cuticle sclerotization process observed in the rbursicon-injected flies. The composite data suggest that md13379 plays a role in regulating the expression of bursicon-regulated genes involved in the cuticle sclerotization process. Arch. Insect Biochem. Physiol. 2008. (c) 2008 Wiley-Liss, Inc.