Molecular cloning and expression of two hexamerin cDNAs from the mosquito,Aedes aegypti

Fourth-instar larvae of Aedes aegypti synthesize two types of hexamerins, H examerin-1 (AaHex-1) and Hexamerin-2 (AaHex-2), whose subunits are distingu ished by different methionine and aromatic amino acid contents. In early fe male pupae only the methionine-rich AaHex-1 gamma subunit accumulates to tw o-fold higher levels than in males. To investigate the relationship between hexamerin structure and the roles of Hex-1 and Hex-2 during mosquito devel opment and reproduction, we have cloned and sequenced cDNAs encoding the Aa Hex-2 alpha, -2 beta and AaHex-1 gamma subunits. Comparison with other inse ct hexamerins revealed that the Aedes Hex-1 and Hex-2 proteins belong, resp ectively, to the two hexamerin subfamilies previously defined for brachycer an Diptera, Probes specific for the Hex-2 alpha and Hex-1 gamma transcripts showed that expression of both genes follows the same developmental timeta ble. However, greater Hex-1 gamma mRNA accumulation may contribute to the h igher levels of Hex-1 gamma protein in early female pupae.