Loosli F, Kmita-Cunisse M, Gehring W J
Biozentrum, Department of Cell Biology, University of Basel, Switzerland.
Proc Natl Acad Sci U S A. 1996 Apr 2;93(7):2658-63. doi: 10.1073/pnas.93.7.2658.
The Pax-6 genes of vertebrates and Drosophila encode transcription factors with highly conserved paired- and homeodomains. They are expressed in the nervous system and the developing eyes. Loss-of-function mutations in mammals and flies lead to a reduction or absence of the eyes. By ectopic expression of Pax-6 in Drosophila ectopic eyes can be induced, indicating a determinative role in eye morphogenesis. We have isolated a Pax-6 homolog of the ribbonworm Lineus sanguineus. This gene shares extensive sequence identity and several conserved splice sites with the mammalian and Drosophila genes. During head regeneration the L. sanguineus Pax-6 homolog is expressed in the central nervous system, in the cerebral organ, and in the eye region. These findings support the hypothesis that Pax-6 was present in primitive metazoa before the evolutionary separation of vertebrates and arthropods and suggest a fundamental role in eye and central nervous system development.
脊椎动物和果蝇的Pax-6基因编码具有高度保守的配对结构域和同源结构域的转录因子。它们在神经系统和发育中的眼睛中表达。哺乳动物和果蝇中的功能丧失突变会导致眼睛缩小或缺失。通过在果蝇中异位表达Pax-6，可以诱导异位眼的形成，这表明其在眼睛形态发生中起决定性作用。我们从纽虫血红纽虫（Lineus sanguineus）中分离出了一个Pax-6同源物。该基因与哺乳动物和果蝇的基因具有广泛的序列同一性和几个保守的剪接位点。在头部再生过程中，血红纽虫的Pax-6同源物在中枢神经系统、脑器官和眼睛区域表达。这些发现支持了这样一种假说，即Pax-6在脊椎动物和节肢动物进化分离之前就存在于原始后生动物中，并表明其在眼睛和中枢神经系统发育中具有重要作用。
