Laboratory for Evolutionary Morphology, Center for Developmental Biology, RIKEN, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe 650-0047, Japan.
Semin Cell Dev Biol. 2013 Feb;24(2):110-8. doi: 10.1016/j.semcdb.2012.12.010. Epub 2013 Jan 3.
The group of Dlx genes belongs to the homeobox-containing superfamily, and its members are involved in various morphogenetic processes. In vertebrate genomes, Dlx genes exist as multiple paralogues generated by tandem duplication followed by whole genome duplications. In this review, we provide an overview of the Dlx gene phylogeny with an emphasis on the chordate lineage. Referring to the Dlx gene repertoire, we discuss the establishment and conservation of the nested expression patterns of the Dlx genes in craniofacial development. Despite the accumulating genomic sequence resources in diverse vertebrates, embryological analyses of Dlx gene expression and function remain limited in terms of species diversity. By supplementing our original analysis of shark embryos with previous data from other osteichthyans, such as mice and zebrafish, we support the previous speculation that the nested Dlx expression in the pharyngeal arch is likely a shared feature among all the extant jawed vertebrates. Here, we highlight several hitherto unaddressed issues regarding the evolution and function of Dlx genes, with special reference to the craniofacial development of vertebrates.
Dlx 基因家族属于同源盒基因超家族，其成员参与多种形态发生过程。在脊椎动物基因组中，Dlx 基因作为串联重复后发生全基因组复制产生的多个基因的旁系同源物而存在。在这篇综述中，我们重点介绍了脊索动物谱系中的 Dlx 基因系统发育概述。参考 Dlx 基因库，我们讨论了 Dlx 基因在颅面发育中的嵌套表达模式的建立和保守性。尽管在不同的脊椎动物中积累了大量的基因组序列资源，但在物种多样性方面，Dlx 基因表达和功能的胚胎学分析仍然有限。通过补充我们对鲨鱼胚胎的原始分析，并结合来自其他硬骨鱼（如老鼠和斑马鱼）的先前数据，我们支持了先前的推测，即在咽弓中嵌套的 Dlx 表达可能是所有现生有颌脊椎动物的共同特征。在这里，我们强调了几个迄今尚未解决的关于 Dlx 基因的进化和功能的问题，特别参考了脊椎动物的颅面发育。
