The two duplicated insecticyanin genes,ins-aandins-bare differentially expressed in the tobacco hornworm,Manduca sexta

Abstract

Two gene-specific probes were generated from the unique sequences in the 3' non-coding regions of the two insecticyanin genes, ins-a and ins-b to study the developmental expression of these genes in Manduca sexta. Both genes were initially transcribed in the freshly hatched first instar larvae and then expressed in the epidermis and to a lesser degree in the fat body during every larval feeding stage. In the epidermis of the 4th and 5th instar larvae, both mRNAs appeared shortly before ecdysis and accumulated to maximal levels within a day. As the larval epidermis became pupally committed on day 3 of the 5th (final) instar, INSa mRNA quickly decreased, whereas INS-b mRNA showed a second peak of accumulation. In the fat body, both genes showed a similar expression pattern within the 4th instar to that of the epidermis except that levels were lower and ins-b mRNA dominated. In the final instar, only ins-b mRNA was present in significant amount. These findings not only reveal that the two duplicated insecticyanin genes have diverged in their expression pattern but also demonstrate, for the first time, that fat body also expresses insecticyanin genes.

Cloning and Expression of a Queen Pheromone-Binding Protein in the Honeybee: an Olfactory-Specific, Developmentally Regulated Protein

“…Although different from ASP2, ASP1 does not share sequence similarity in common with vertebrate OBPs (Pelosi, 1994), known as lipocalins, a superfamily of proteins that have been also found in bacteria (Flower et al, 1995) and insects (Li and Riddiford, 1992). Despite their comparative functional and biochemical properties, olfactory proteins presenting significant sequence similarity to both insect and vertebrate OBPs have not yet been found.…”

Hormonal regulation of JP29 in the epidermis during larval development and metamorphosis in the tobacco hornworm,Manduca sexta

“…In the larva, the developmental profile of JP29 mRNA is similar to that of insecticyanin Li and Riddiford, 1994) and the larval cuticle protein LCP14 (Rebers and Riddiford, 1988;Hiruma et al, 1991). All three mRNAs decline in response to the rise of ecdysteroid for the molt and reappear after the molt.…”

Comparative analysis of two biliproteins, BP1 and BP2, from haemolymph of cabbage white butterfly,Pieris rapae

“…7 (Riddiford, 1981(Riddiford, , 1982Li and Riddiford, 1992;Beckage and Kanost, 1993;Li and Riddiford, 1994) and P. brassicae BBP in the fat body, gonads, and epidermis, and secreted into the haemolymph and cuticle (Li and Riddiford, 1994;Schmidt and Skerra, 1994). Saito (1993) (Riddiford, 1982;Kiely and Riddiford, 1985;Riddiford et al, 1990).…”

“…Although BBP and INS are two closely-related members of the lepidopteran lipocalin family, their expression shows distinct temporal and tissue specificity (Li and Riddiford, 1994). During development, BBP gene is expressed in larvae, pupae, and adults, while INS-a and INS-b are expressed only in the larvae.…”