Xue L, Noll M
Institute for Molecular Biology (II), University of Zürich, Switzerland.
EMBO J. 1996 Jul 15;15(14):3722-31.
Drosophila paired- embryos can be rescued to viable adults by the evolutionary alleles prd-Gsb and prd-Pax3, which express the Drosophila Gooseberry and mouse Pax3 proteins under the control of the paired cis-regulatory region. As prd-Gsb uncovers a prd function involved in the proper abdominal segmentation of adults, evolutionary alleles, defined and constructed in this manner, may often be weak and thus serve to discover hitherto unknown functions of a gene. Our findings show that the Gooseberry and Pax3 proteins have conserved most or all functions of the related Drosophila Paired protein although their C-terminal halves appear unrelated in sequence but not in 3-D structure essential for function. It follows that the acquisition of new cis-regulatory regions rather than the divergence of the C-terminal coding regions has been the primary device for the functional diversification of the Drosophila genes paired and gooseberry and the mouse Pax3 gene. The operation of this mechanism in insects as well as vertebrates suggests a major role in evolution.
果蝇配对基因缺失的胚胎可以通过进化等位基因prd-Gsb和prd-Pax3拯救为有活力的成虫，这两个等位基因在配对顺式调控区域的控制下表达果蝇醋栗蛋白和小鼠Pax3蛋白。由于prd-Gsb揭示了一个与成虫腹部正确分段有关的prd功能，以这种方式定义和构建的进化等位基因可能通常较弱，因此有助于发现一个基因迄今未知的功能。我们的研究结果表明，醋栗蛋白和Pax3蛋白保留了相关果蝇配对蛋白的大部分或全部功能，尽管它们的C端序列看似不相关，但对功能至关重要的三维结构却并非如此。由此可见，获得新的顺式调控区域而非C端编码区域的分化，是果蝇配对基因和醋栗基因以及小鼠Pax3基因功能多样化的主要机制。这种机制在昆虫和脊椎动物中的运作表明其在进化中起主要作用。
