Detection of homeobox genes in development and evolution.

The homeobox genes encode a family of DNA-binding regulatory proteins whose function and genomic organization make them an important model system for the study of development and differentiation. Oligonucleotide primers corresponding to highly conserved regions of Antennapediaclass homeodomains were designed to detect and identify homeobox sequences in populations of DNA or RNA by means of the polymerase chain reaction (PCR). Here we present a survey of sequences detected by PCR using an initial set of primers (HoxA and HoxB) based on an early nucleotide consensus for vertebrate Antennapedia-class homeodomains. Several novel sequences are reported from both mouse genomic DNA and RNA from the developing mouse telencephalon. Forebrain-derived clones are similar to the chicken CHox7, Drosophila H2.0, and mouse Hlx genes. PCR also proved to be a rapid method for identifying homeobox sequences from diverse metazoan species. Cloning of three Antennapedia-related sequences from cnidarians provides evidence of ancient roles for homeobox genes early in metazoan evolution. IMAGES:

同源框基因（homeobox genes）编码一类DNA结合型调控蛋白，其功能与基因组组织特征使其成为发育与分化研究领域的重要模型系统。针对触角足类同源结构域（Antennapedia-class homeodomains）的高度保守区域设计的寡核苷酸引物，可通过聚合酶链式反应（PCR）在DNA或RNA样本群体中检测并鉴定同源框序列。本研究基于脊椎动物触角足类同源结构域的早期核苷酸保守共识序列，使用首批引物（HoxA与HoxB），通过PCR技术对检测得到的序列进行了系统性普查分析。本研究从小鼠基因组DNA以及发育中小鼠端脑的RNA样本中，鉴定出多个全新的同源框序列。前脑来源的克隆序列与鸡CHox7基因、果蝇（Drosophila）H2.0基因以及小鼠Hlx基因具有高度同源性。实验证实，PCR可作为一种快速高效的方法，从多样的后生动物（metazoan）物种中鉴定同源框序列。从刺胞动物（cnidarians）中克隆得到的3个触角足类相关序列，为同源框基因在后生动物演化早期即发挥古老功能提供了实验证据。图片：