Effects of classical insect hormones on the expression profiles of a lipase gene from the cotton bollworm (Helicoverpa armigera)

A 967-bp cDNA, encoding a 31 kDa lipase with an isoelectric point of 8.8, was cloned from Helicoverpa armigera. The gene was named Ha-lipase. The Ha-lipase transcript was present in the head-thorax, midgut and fat body but not in integument and haemocytes from 5th instar larvae, with higher expression levels in feeding larvae than that in molting larvae. In the midgut, transcription of the gene during the 5th instar larval period was lower than during the 6th instar period. While in the fat body, lipase was not found at the 6th instar stage but only at the 5th instar stage. The expression of Ha-lipase could be up-regulated by methoprene and down-regulated by methoxyfenozide (RH-2485) and 20-hydroxyecdysone (20E).