Peters T, Dildrop R, Ausmeier K, Rüther U
Entwicklungs- und Molekularbiologie der Tiere, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany.
Genome Res. 2000 Oct;10(10):1453-62. doi: 10.1101/gr.144100.
Iroquois proteins comprise a conserved family of homeodomain-containing transcription factors involved in patterning and regionalization of embryonic tissues in both vertebrates and invertebrates. Earlier studies identified four murine Iroquois (Irx) genes. Here we report the isolation of two additional members of the murine gene family, Irx5 and Irx6. Phylogenetic analysis of the Irx gene family revealed distinct clades for fly and vertebrate genes, and vertebrate members themselves were classified into three pairs of cognate genes. Mapping of the murine Irx genes identified two gene clusters located on mouse chromosomes 8 and 13, respectively. Each gene cluster is represented by three Irx genes whose relative positions within both clusters are strictly conserved. Combined results from phylogenetic, linkage, and physical mapping studies provide evidence for the evolution of two Irx gene clusters by duplication of a larger chromosomal region and dispersion to two chromosomal locations. The maintenance of two cognate Irx gene clusters during vertebrate evolution suggests that their genomic organization is important for the regulation, expression, and function of Irx genes during embryonic development.
易洛魁蛋白构成了一个保守的含同源结构域转录因子家族，参与脊椎动物和无脊椎动物胚胎组织的模式形成和区域化。早期研究鉴定出了四个小鼠易洛魁（Irx）基因。在此，我们报告了小鼠基因家族另外两个成员Irx5和Irx6的分离。Irx基因家族的系统发育分析揭示了果蝇和脊椎动物基因的不同进化枝，并且脊椎动物成员本身被分为三对同源基因。小鼠Irx基因的定位确定了分别位于小鼠8号和13号染色体上的两个基因簇。每个基因簇由三个Irx基因代表，它们在两个簇中的相对位置严格保守。系统发育、连锁和物理定位研究的综合结果为两个Irx基因簇通过一个更大染色体区域的复制并分散到两个染色体位置的进化提供了证据。脊椎动物进化过程中两个同源Irx基因簇的保留表明它们的基因组组织对于胚胎发育过程中Irx基因的调控、表达和功能很重要。
