MOLECULAR-CLONING OF 3 DISTINCT CDNAS, EACH ENCODING A DIFFERENT ADIPOKINETIC HORMONE PRECURSOR, OF THE MIGRATORY LOCUST, LOCUSTA-MIGRATORIA - DIFFERENTIAL EXPRESSION OF THE DISTINCT ADIPOKINETIC HORMONE PRECURSOR GENES DURING FLIGHT ACTIVITY

Three distinct cDNAs encoding the preproadipokinetic hormones I, II, and III (prepro AKH I, II, and III), respectively, of Locusta migratoria have been isolated and sequenced. The three L. migratoria AKH precursors have an overall architecture similar to that of other precursors of the AKH/red pigment-concentrating hormone (RPCH) family identified so far. The AKH I and LT precursors of L. migratoria are highly homologous to the Schistocerca gregaria and Schistocerca nitans AKH precursors. Although the L. migratoria AKH LII precursor appears to be the least homologous to the Manduca sexta, Drosophila melanogaster, and Carcinus maenas AKH/RPCH precursors, we favor the opinion that the L. migratoria AKH III precursor is evolutionary more related to the M. sexta, D. melanogaster, and C. maenas AKH/RPCH precursors than to the AKH I and II precursors of S. gregaria, S. nitans, or L. migratoria. In situ hybridization showed signals for the different AKH mRNAs to be co-localized in cell bodies of the glandular lobes of the corpora cardiaca. Northern blot analysis revealed the presence of single mRNA species encoding the AKH I precursor (similar to 570 bases), AKH II precursor (similar to 600 bases), and AHA III precursor (similar to 670 bases), respectively. Interestingly, flight activity increased steady-state levels of the AKH I and II mRNAs (similar to 2.0 times each) and the AHA III mRNA (similar to 4.2 times) in the corpora cardiaca.