Cloning of cDNA for a juvenile hormone-regulated oothecin mRNA

Oothecins, the structural proteins of the egg case of the cockroach Periplaneta americana, have a high content of a few amino acids. This allowed cDNA cloned in the phage M13 to be directly screened for the presence of sequences derived from glycine-rich oothecins by selective DNA sequence analysis. One cDNA fragment codes for the major oothecin synthesised by the left colleterial gland. Part of its derived amino-acid sequence contains a repeated pentapeptide, Gly.Gly.Leu.Gly.Tyr, which is identical to the tandemly repeated consensus pentapeptide in silkmoth chorion proteins. Oothecin synthesis in the left colleterial gland is dependent on the presence of juvenile hormone. A probe from the cDNA segment coding for the major glycine-rich oothecin was used to measure the induction of the corresponding RNA during maturation of the colleterial gland after adult emergence.