title: Molecular cloning and expression of a hexamerin cDNA from the malaria mosquito, Anopheles gambiae.
abstract: During the last larval instar, dipteran insects synthesize two hexamerins rich in aromatic residues, typified by the larval serum proteins 1 and 2 (LSP-1 and LSP-2) of Drosophila melanogaster. We report here the characterization of a complete cDNA sequence encoding a LSP-1-like protein from a lower dipteran insect, the malaria mosquito Anopheles gambiae. The cDNA encodes the subunit of a homohexamer, A. gambiae hexamerin-1.1 (AgHex-1.1), which is a major pupal protein but only a minor constituent of late larval hemolymph. AgHex-1.1 is moderately rich in methionine (3.9%) and particularly rich in aromatic residues (21% Phe+Tyr). Cytogenetic analysis reveals AgHex-1.1 to be encoded by a single-copy gene localized to division 22F within the proximal 2La inversion breakpoint of chromosome 2 of A. gambiae. The AgHex-1.1 transcript is first detected in fourth-instar larvae (L4) and disappears abruptly in early pupae. In situ hybridization shows accumulation of the transcript uniquely in the larval fat body. AgHex-1.1 mRNA is re-expressed in male and female adults at about 10% of the L4 level, with no effect of bloodfeeding in females. The potential roles of AgHex-1.1 in Anopheles development and reproductive maturation are discussed.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock 72205, USA.
authors.forename: S O
authors.initials: SO
authors.lastname: Zakharkin
authors.forename: A V
authors.initials: AV
authors.lastname: Gordadze
authors.forename: S E
authors.initials: SE
authors.lastname: Korochkina
authors.forename: K D
authors.initials: KD
authors.lastname: Mathiopoulos
authors.forename: A
authors.initials: A
authors.lastname: Della Torre
authors.forename: H
authors.initials: H
authors.lastname: Benes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004175:Diptera; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D005216:Fat Body / Q000737:chemistry; D005260:Female; D015698:Genomic Library; D006458:Hemolymph / Q000737:chemistry; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000737:chemistry; D008297:Male; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D029721:Drosophila Proteins; D019476:Insect Proteins; D012333:RNA, Messenger; C034648:larval serum protein, Drosophila; C041137:storage proteins, Insecta