Garriock Robert J, Warkman Andrew S, Meadows Stryder M, D'Agostino Susan, Krieg Paul A
Department of Cell Biology and Anatomy, University of Arizona Health Sciences Center, Tucson, Arizona 85724, USA.
Dev Dyn. 2007 May;236(5):1249-58. doi: 10.1002/dvdy.21156.
The Wnt family of growth factors regulate many different aspects of embryonic development. Assembly of the complete mouse and human genome sequences, plus expressed sequence tag surveys have established the existence of 19 Wnt genes in mammalian genomes. However, despite the importance of model vertebrates for studies in developmental biology, the complete complement of Wnt genes has not been established for nonmammalian genomes. Using genome sequences for chicken (Gallus gallus), frog (Xenopus tropicalis), and fish (Danio rerio and Tetraodon nigroviridis), we have analyzed gene synteny to identify the orthologues of all 19 human Wnt genes in these species. We find that, in addition to the 19 Wnts observed in humans, chicken contained an additional Wnt gene, Wnt11b, which is orthologous to frog and zebrafish Wnt11 (silberblick). Frog and fish genomes contained orthologues of the 19 mammalian Wnt genes, plus Wnt11b and several duplicated Wnt genes. Specifically, the Xenopus tropicalis genome contained 24 Wnt genes, including additional copies of Wnt7-related genes (Wnt7c) and 3 recent Wnt duplications (Wnt3, Wnt9b, and Wnt11). The Danio rerio genome contained 27 Wnt genes with additional copies of Wnt2, Wnt2b, Wnt4b, Wnt6, Wnt7a, and Wnt8a. The presence of the additional Wnt11 sequence (Wnt11b) in the genomes of all ancestral vertebrates suggests that this gene has been lost during mammalian evolution. Through these studies, we identified the frog orthologues of the previously uncharacterized Wnt2, Wnt3, Wnt9a, Wnt9b, Wnt10a, and Wnt16 genes and their expression has been characterized during early Xenopus development.
Wnt生长因子家族调控胚胎发育的许多不同方面。完整的小鼠和人类基因组序列的汇编，加上表达序列标签调查，已证实哺乳动物基因组中存在19个Wnt基因。然而，尽管模式脊椎动物在发育生物学研究中很重要，但非哺乳动物基因组中Wnt基因的完整组成尚未确定。利用鸡（原鸡）、青蛙（热带爪蟾）和鱼类（斑马鱼和黑点青鳉）的基因组序列，我们分析了基因共线性，以确定这些物种中所有19个人类Wnt基因的直系同源基因。我们发现，除了在人类中观察到的19个Wnt基因外，鸡还含有一个额外的Wnt基因Wnt11b，它与青蛙和斑马鱼的Wnt11（silberblick）直系同源。青蛙和鱼类基因组包含19个哺乳动物Wnt基因的直系同源基因，加上Wnt11b和几个重复的Wnt基因。具体而言，热带爪蟾基因组包含24个Wnt基因，包括Wnt7相关基因（Wnt7c）的额外拷贝和3个最近的Wnt重复基因（Wnt3、Wnt9b和Wnt11）。斑马鱼基因组包含27个Wnt基因，有Wnt2、Wnt2b、Wnt4b、Wnt6、Wnt7a和Wnt8a的额外拷贝。所有原始脊椎动物基因组中都存在额外的Wnt11序列（Wnt11b），这表明该基因在哺乳动物进化过程中丢失了。通过这些研究，我们鉴定了之前未表征的Wnt2、Wnt3、Wnt9a,、Wnt9b、Wntl0a和Wnt16基因的青蛙直系同源基因，并对其在爪蟾早期发育过程中的表达进行了表征。
