Hemavathy K, Ashraf S I, Ip Y T
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Gene. 2000 Oct 17;257(1):1-12. doi: 10.1016/s0378-1119(00)00371-1.
The existence of homologous genes in diverse species is intriguing. A detailed comparison of the structure and function of gene families may provide important insights into gene regulation and evolution. An unproven assumption is that homologous genes have a common ancestor. During evolution, the original function of the ancestral gene might be retained in the different species which evolved along separate courses. In addition, new functions could have developed as the sequence began to diverge. This may also explain partly the presence of multipurpose genes, which have multiple functions at different stages of development and in different tissues. The Drosophila gene snail is a multipurpose gene; it has been demonstrated that snail is critical for mesoderm formation, for CNS development, and for wing cell fate determination. The related vertebrate Snail and Slug genes have also been proposed to participate in mesoderm formation, neural crest cell migration, carcinogenesis, and apoptosis. In this review, we will discuss the Snail/Slug family of regulators in species ranging from insect to human. We will present the protein structures, expression patterns, and functions based on molecular genetic analyses. We will also include the studies that helped to elucidate the molecular mechanisms of repression and the relationship between the conserved and divergent functions of these genes. Moreover, the studies may enable us to trace the evolution of this gene family.
不同物种中同源基因的存在很有趣。对基因家族的结构和功能进行详细比较可能会为基因调控和进化提供重要见解。一个未经证实的假设是同源基因有一个共同的祖先。在进化过程中，祖先基因的原始功能可能会保留在沿着不同路径进化的不同物种中。此外，随着序列开始分化，可能会发展出新的功能。这也可以部分解释多功能基因的存在，这些基因在发育的不同阶段和不同组织中具有多种功能。果蝇的蜗牛基因就是一个多功能基因；已经证明蜗牛基因对于中胚层形成、中枢神经系统发育以及翅细胞命运决定至关重要。相关的脊椎动物蜗牛基因和蛞蝓基因也被认为参与中胚层形成、神经嵴细胞迁移、致癌作用和细胞凋亡。在这篇综述中，我们将讨论从昆虫到人类等物种中的蜗牛/蛞蝓调节因子家族。我们将基于分子遗传学分析介绍其蛋白质结构、表达模式和功能。我们还将纳入有助于阐明抑制分子机制以及这些基因保守和分化功能之间关系的研究。此外，这些研究可能使我们能够追溯这个基因家族的进化历程。
