Molecular characterization of the VLDL receptor homolog mediating binding of lipophorin in oocyte of the mosquito Aedes aegypti.

Autor(es): Cheon H M; Seo S J; Sun J; Sappington T W; Raikhel A S

Resumo: Lipophorin (Lp) functions as a yolk protein precursor in the mosquito Aedes aegypti and it is internalized via receptor-mediated endocytosis (Insect Biochem. Mol. Biol., 30 (2000) 1161). We cloned and molecularly characterized a putative mosquito ovarian lipophorin receptor (AaLpRov) cDNA. The cDNA has a length of 3468 bp coding for a 1156-residue protein with a predicted molecular mass of 128.9 kDa. The deduced amino acid sequence of the cDNA revealed that it encodes a protein homolog of the LDL receptor superfamily, and that it harbors eight cysteine-rich ligand binding repeats at the N-terminus like vertebrate VLDL receptors. The deduced amino acid sequence of this mosquito ovarian receptor is most similar to that of the locust lipophorin receptor (LmLpR) (64.3%), and is only distantly related to the mosquito vitellogenin receptor (VgR) (18.3%), another ovarian LDLR homolog with a different ligand. The AaLpRov cDNA was expressed in a TnT Coupled Reticulocyte Lysate system, and co-immunoprecipitation experiments confirmed that the receptor protein specifically binds Lp. Developmental expression profiles clearly showed that AaLpRov transcripts are present in the vitellogenic ovary, with peak expression at 24-36 h post blood meal. In situ hybridization indicated that AaLpRov transcripts are present only in female germ line cells. Distance-based phylogenetic analyses suggest that the insect LpR and vertebrate LDL/VLDL receptor lineages separated after divergence from the insect VgR lineage.

Palavras-Chave: Mosquito; Lipophorin receptor; Egg development; Receptor-mediated endocytosis; Low density lipoprotein receptor family

Imprenta: Insect Biochemistry and Molecular Biology, v. 31, n. 8, p. 753-760, 2001

Identificador do objeto digital: 10.1016/S0965-1748(01)00068-6

Descritores: Aedes aegypti - Cell ; Aedes aegypti - DNA ; Aedes aegypti - Genome ; Aedes aegypti - Molecular Structure ; Aedes aegypti - Pathogenesis ; Aedes aegypti - Proteins

Data de publicação: 2001