title: Molecular characterization and evolution of a gene family encoding both female- and male-specific reproductive proteins in Drosophila.
abstract: Gene duplication is an important mechanism for the evolution of new reproductive proteins. However, in most cases, each resulting paralog continues to function within the same sex. To investigate the possibility that seminal fluid proteins arise through duplicates of female reproductive genes that become "co-opted" by males, we screened female reproductive genes in Drosophila melanogaster for cases of duplication in which one of the resulting paralogs produces a protein in males that is transferred to females during mating. We identified a set of three tandemly duplicated genes that encode secreted serine-type endopeptidase homologs, two of which are expressed primarily in the female reproductive tract (RT), whereas the third is expressed specifically in the male RT and encodes a seminal fluid protein. Evolutionary and gene expression analyses across Drosophila species suggest that this family arose from a single-copy gene that was female-specific; after duplication, one paralog evolved male-specific expression. Functional tests of knockdowns of each gene in D. melanogaster show that one female-expressed gene is essential for full fecundity, and both female-expressed genes contribute singly or in combination to a female's propensity to remate. In contrast, knockdown of the male-expressed paralog had no significant effect on female fecundity or remating. These data are consistent with a model in which members of this gene family exert effects on females by acting on a common, female-expressed target. After duplication and male co-option of one paralog, the evolution of the interacting proteins could have resulted in differential strengths or effects of each paralog.
authors.affiliation: Department of Molecular Biology and Genetics, Cornell UniversityDepartment of Biology, College of Wooster.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Sirot
authors.affiliation: Department of Molecular Biology and Genetics, Cornell UniversityDepartment of Biology, College of the Holy Cross.
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Findlay
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Sitnik
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University.
authors.forename: Dorina
authors.initials: D
authors.lastname: Frasheri
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Avila
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University mfw5@cornell.edu.
authors.forename: Mariana F
authors.initials: MF
authors.lastname: Wolfner
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D005298:Fertility / Q000235:genetics; D020440:Gene Duplication; D015870:Gene Expression; D017344:Genes, Insect; D008297:Male; D008957:Models, Genetic; D005810:Multigene Family; D010802:Phylogeny; D012098:Reproduction / Q000235:genetics; D012727:Sex Characteristics
chemical_list: D029721:Drosophila Proteins
keywords: Drosophila; gene duplication; protease; seminal proteins; sex-specific expression; spermathecal proteins