transformer gene in Bactrocera oleae: the genetic switch that determines its sex fate

• Published in: Insect molecular biology Vol. 16; no. 2; pp. 221 - 230
• Main Authors: Lagos, D, Koukidou, M, Savakis, C, Komitopoulou, K
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.04.2007; Blackwell Publishing Ltd
• Subjects: Amino Acid Sequence; Animals; Bactrocera oleae; Female; Fertility; Genome, Insect; Homeostasis - genetics; Insect Proteins - genetics; Karyotyping; Male; Molecular Sequence Data; Nuclear Proteins - genetics; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Double-Stranded; Sequence Analysis, DNA; sex determination; Sex Determination Processes; sex-specific splicing; Tephritidae - genetics; transformer
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1111/j.1365-2583.2006.00717.x

Transformer (tra) is the second gene of a regulatory cascade based on RNA splicing that determines sex in Drosophila melanogaster. Splicing of tra transcripts is regulated by the master gene Sex lethal and tra itself regulates splicing of the transcriptional regulator doublesex (dsx). We present the isolation and characterization of Botra, the olive fruit fly Bactrocera oleae orthologue to the Drosophila gene transformer. As in Drosophila, Botra transcripts are spliced in a sex-specific manner so that only females encode a functional polypeptide of 422 amino acids, whereas males encode presumably nonfunctional peptide(s). The identification of multiple TRA/TRA-2 binding sites within the Botra male-specific exons, suggests an autoregulation mechanism of tra, through TRA/TRA2 activities. The fundamental role of the TRA protein in sex determination of Bactrocera was investigated by RNA interference, where the introduction of Botra dsRNA into embryos resulted in complete transformation of XX flies into fertile males.