Lipophorin is the major hemolymph
protein responsible for
lipid transport among tissues of insects. This
protein may be a
lipid source for the development and reproduction of human
malaria parasites in mosquitoes, and therefore could be a target to disrupt
malaria parasite development in the vector. The
lipophorin of Anopheles gambiae was purified by
KBr gradient ultracentrifugation and showed variation in density from 1.111 to 1.143 g/ml during development. The amount and density of
lipophorin increase in blood-fed females, indicating an adaptation of vitellogenic mosquitoes to an elevated rate of
lipid transport to the developing eggs. The A. gambiae
lipophorin gene is composed of eight exons and transcribes an
mRNA that is 10,516
nucleotides in length. The predicted initial translation product is a preproapoliphorin consisting of 3332
amino acids, which is processed by proteolysis to generate two mature apolipophorins: apolipophorin-I (Mr = 280,000) and
apolipophorin-II (Mr = 81,000). The gene is expressed in the fat body tissues throughout development. An elevated transcriptional activity of the
lipophorin gene during vitellogenesis is consistent with the presence of putative cis-regulatory elements (GATA and
ecdysone responsive elements) in its 3'-end flanking DNA sequence.