Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK.
Gene. 2011 Dec 1;489(1):30-40. doi: 10.1016/j.gene.2011.08.007. Epub 2011 Aug 31.
In the human genome, members of the FoxC, FoxF, FoxL1, and FoxQ1 gene families are found in two paralagous clusters. One cluster contains the genes FOXQ1, FOXF2, FOXC1 and the second consists of FOXF1, FOXC2, and FOXL1. In jawed vertebrates these genes are known to be expressed in different pharyngeal tissues and all, except FoxQ1, are involved in patterning the early embryonic mesoderm. We have previously traced the evolution of this cluster in the bony vertebrates, and the gene content is identical in the dogfish, a member of the most basally branching lineage of the jawed vertebrates. Here we extend these analyses to jawless vertebrates. Using genomic searches and molecular approaches we have identified homologues of these genes from lampreys. We identify two FoxC genes, two FoxF genes, two FoxQ1 genes and single FoxL1 gene. We examine the embryonic expression of one predominantly mesodermally expressed gene family, FoxC, and the endodermally expressed member of the cluster, FoxQ1. We identified FoxQ1 transcripts in the pharyngeal endoderm, while the two FoxC genes are differentially expressed in the pharyngeal mesenchyme and ectoderm. Furthermore we identify conserved expression of lamprey FoxC genes in the paraxial and intermediate mesoderms. We interpret our results through a chordate-wide comparison of expression patterns and discuss gene content in the context of theories on the evolution of the vertebrate genome.
在人类基因组中，FoxC、FoxF、FoxL1 和 FoxQ1 基因家族的成员存在于两个平行的簇中。一个簇包含 FOXQ1、FOXF2 和 FOXC1 基因，而另一个簇则由 FOXF1、FOXC2 和 FOXL1 基因组成。在有颌脊椎动物中，这些基因已知在不同的咽组织中表达，除了 FoxQ1 之外，它们都参与了早期胚胎中胚层的模式形成。我们之前已经追踪了这个基因簇在硬骨鱼类中的进化，并且在鲨鱼中，这个基因簇的基因内容是相同的，鲨鱼是有颌脊椎动物中最基础的分支谱系的成员。在这里，我们将这些分析扩展到无颌脊椎动物。通过基因组搜索和分子方法，我们从七鳃鳗中鉴定出了这些基因的同源物。我们鉴定出了两个 FoxC 基因、两个 FoxF 基因、两个 FoxQ1 基因和一个 FoxL1 基因。我们研究了一个主要在中胚层表达的基因家族 FoxC 和该基因簇中内胚层表达的成员 FoxQ1 的胚胎表达。我们在咽内胚层中鉴定到了 FoxQ1 转录本，而两个 FoxC 基因则在咽间充质和外胚层中差异表达。此外，我们还鉴定到七鳃鳗 FoxC 基因在轴旁中胚层和中间中胚层中的保守表达。我们通过对整个脊索动物的表达模式进行比较，解释了我们的结果，并讨论了基因内容在脊椎动物基因组进化理论中的意义。
