Lagos D, Koukidou M, Savakis C, Komitopoulou K
Division of Genetics and Biotechnology, Department of Biology, University of Athens, Panepistimiopolis, Kouponia, Athens, Greece.
Insect Mol Biol. 2007 Apr;16(2):221-30. doi: 10.1111/j.1365-2583.2006.00717.x. Epub 2007 Feb 6.
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.
Transformer（tra）是基于RNA剪接的调控级联反应中的第二个基因，该反应决定了黑腹果蝇的性别。tra转录本的剪接受主基因性致死基因调控，而tra本身则调控转录调节因子双性基因（dsx）的剪接。我们展示了橄榄果蝇实蝇（Bactrocera oleae）中与果蝇基因transformer同源的Botra的分离和特征。与果蝇一样，Botra转录本以性别特异性方式进行剪接，因此只有雌性编码一个由422个氨基酸组成的功能性多肽，而雄性编码可能无功能的肽段。在Botra雄性特异性外显子内鉴定出多个TRA/TRA-2结合位点，提示通过TRA/TRA2活性对tra进行自我调节的机制。通过RNA干扰研究了TRA蛋白在实蝇性别决定中的基本作用，将Botra双链RNA导入胚胎会导致XX果蝇完全转变为可育雄性。
