Doublesex (dsx) is a double-switch gene at the bottom of the somatic sex-determination hierarchy which regulates sexual dimorphism in many insects. Here, Drosophila melanogaster homologues of dsx were isolated in two Bactrocera species, the oriental fruit fly, B. dorsalis, and the guava fruit fly, B. correcta. Results of RT-PCR analysis suggests that both the B. dorsalis dsx (Bd1dsx) and B. correcta dsx (Bcdsx) genes are transcribed and sex-specifically spliced in accordance with the Drosophila sex-specific splicing mechanism. The cDNA sequences shared a high degree of similarity at the nucleotide level among the Bactrocera species. Structurally conserved domains for DNA-binding and oligomerization were observed in all transcripts suggesting that their proteins function as transcriptional factors for downstream sex-specific gene expression. A purine-rich element (PRE) and four repeat elements (dsxRE) for TRA/TRA-2 binding sites were also found in the 3' untranslated regions (UTR) of both the female Bd1dsx and Bcdsx mRNAs. Notably, a putative core promoter was revealed in Bd1dsx, being probably the first dsx promoter discovered in the tephritid flies.
Abstract. Bactrocera fruit flies are ranked among the most destructive pests of the worldwide fruit and vegetable trades. Coding regions of two oligomerization domains within doublesex (dsx) genes were determined in Bactrocera dorsalis (oriental fruit fly) and B. correcta (guava fruit fly). Resulting sequences revealed a high degree of similarity at both nucleotide and putative amino acid levels in the genus Bactrocera. Conservation of the DNA-binding DM motif and several known molecular features within the domains suggest a presence of strong purifying selection on the DSX proteins. Topology of the phylogenetic gene trees and deduced amino acid substitution patterns suggest that the coding region sequences of the two domains are diversified in concert parallel with the species differentiation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.