Regulation and correlation of X chromosomal puff and glue protein synthesis in the larval salivary glands of Drosophila nasuta nasuta

We have attempted to identify the chromosomal region harboring genes encoding major glue fractions by correlating the glue protein synthesis with the puffing pattern of the X-chromosome of Drosophila nasuta nasuta during normal larval development and in the presence of exogenous 20-OH Ecdysone. The division 10 of the X-chromosome was characterized by the presence of a puff right from early third instar which attains its maximum size in the mid third instar stage and remains active till the onset of prepupal stage. The puff was found to regress when larvae/ glands were exposed to exogenous 20-OH Ecdysone in vivo or in vitro, suggesting that it is an intermolt puff. Salivary glands treated with 20-OH Ecdysone revealed a significant reduction in the total protein content as well as X-linked glue fractions resolved by SDS–PAGE.