Characterization of the insect cuticle sclerotization hormone bursicon and bursicon-regulated genes in the house fly Musca domestica

Bursicon is a neurohormone that regulates cuticle sclerotization (tanning and hardening) and the wing expansion processes in insects. Bursicon was discovered over forty years ago from the blowfly Calliphora erythrocephala in a neck-ligated fly assay. However due to the difficulties in hormone protein purification and the lack of molecular techniques, the genes encoding bursicon were not identified until in the years of 2004-2005. Studies in Drosophila melanogaster have indicated that bursicon is actually a heterodimeric cystine knot family protein containing two subunits, bursicon α (bur α or burs) and bursicon β (bur β or pburs), which are encoded by two individual genes burs α and burs β (or burs and pburs). Although bursicon genes have been cloned from several insect species or predicted from insect genomes, little is known about its mechanisms in the cuticle sclerotization and wing expansion processes, especially the signal transduction pathway(s) and the genes regulated by bursicon.