title: Mosquito dopa decarboxylase cDNA characterization and blood-meal-induced ovarian expression.
abstract: Dopa decarboxylase (DDC) functions in insect catecholamine biochemistry to produce materials essential for cross-linking reactions that result in tanning and/or melanization, include tanning of the mosquito egg chorion and encapsulation of parasites. We have cloned Ddc from the mosquito, Aedes aegypti, and studied its expression in response to blood-feeding, which initiates events necessary for egg maturation in mosquitoes. The Ae. aegypti Ddc cDNA was isolated via heterologous screening using a clone from Drosophila melanogaster. A resulting 1.87 kilobase (kb) clone was sequenced to reveal an open reading frame of 1464 bp, as well as 5'- and 3'-untranslated segments. The inferred amino acid sequence of this clone shares 81% identity with the published Drosophila Ddc cDNA, including complete identity with twenty-four contiguous amino acids encompassing the pyridoxal-5-phosphate cofactor binding domain. Analysis of an F2 intercross population derived from a parental cross between two Ae. aegypti strains (Hamburg and Moyo-In-Dry) allowed us to map Ddc to a locus on linkage group 2. Expression studies demonstrated the presence of a 2.1 kb message, the majority of which occurs in the ovaries where Ddc-specific mRNA is up-regulated in response to ingestion of a blood meal. The potential for egg-tanning in anautogenous mosquitoes as a model for understanding specific genetic events in the regulation of catecholamine metabolism is addressed.
authors.affiliation: Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Ferdig
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: D W
authors.initials: DW
authors.lastname: Severson
authors.forename: B M
authors.initials: BM
authors.lastname: Christensen
mesh_terms: D000330:Aedes / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004296:Dopa Decarboxylase / Q000235:genetics*; D004331:Drosophila melanogaster; D005260:Female; D015870:Gene Expression; D008969:Molecular Sequence Data; D010053:Ovary / Q000378:metabolism; D012150:Polymorphism, Restriction Fragment Length; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D004296:Dopa Decarboxylase