Saccone G, Peluso I, Artiaco D, Giordano E, Bopp D, Polito L C
Dipartimento di Genetica, Biologia generale e Moleculare, Universitá degli Studi di Napoli 'Federico II', Napoli, Italy.
Development. 1998 Apr;125(8):1495-500. doi: 10.1242/dev.125.8.1495.
In Drosophila, Sxl functions as a binary switch in sex determination. Under the control of the primary sex-determining signal, it produces functional protein only in XX animals to implement female development. Here we report that, in contrast to Drosophila, the Sxl homologue in the Medfly, Ceratitis capitata, expresses the same mRNAs and protein isoforms in both XX and XY animals irrespective of the primary sex-determining signal. Also, experiments with two inducible transgenes demonstrate that the corresponding Ceratitis SXL product has no significant sex-transforming effects when expressed in Drosophila. Similar results have been obtained for the Sxl homologue of Musca domestica (Meise, M., Hilfiker-Kleiner, D., Brunner, C., DŁbendorfer, A., N¿thiger, R. and Bopp, D. (1998) Development 125, 1487-1494). Our findings suggest that Sxl acquired its master regulatory role in sex determination during evolution of the Acalyptratae group, most probably after phylogenetic divergence of the genus Drosophila from other genera of this group.
在果蝇中，性梳基因（Sxl）在性别决定过程中起着二元开关的作用。在初级性别决定信号的控制下，它仅在XX个体中产生功能性蛋白质，以实现雌性发育。在此我们报告，与果蝇不同，地中海实蝇（Ceratitis capitata）中的Sxl同源物，无论初级性别决定信号如何，在XX和XY个体中均表达相同的mRNA和蛋白质异构体。此外，对两个可诱导转基因的实验表明，相应的地中海实蝇SXL产物在果蝇中表达时没有显著的性别转化效应。家蝇的Sxl同源物也得到了类似的结果（Meise, M., Hilfiker-Kleiner, D., Brunner, C., DŁbendorfer, A., N¿thiger, R.和Bopp, D. (1998) Development 125, 1487 - 1494）。我们的研究结果表明，性梳基因在无瓣蝇类群的进化过程中，很可能是在果蝇属与该类群其他属发生系统发育分歧之后，才在性别决定中获得了其主要调控作用。
