The Roles of Segmentation Gene Homologues in Annelids

0090378保存目前对动物细胞分化和模式形成的理解在很大程度上是基于从果蝇黑腹果蝇等‘模型’系统获得的数据。目前尚不清楚苍蝇的发育机制在多大程度上被其他门所保守。这个问题将通过检查苍蝇发育调控基因的环节同源基因及其在身体计划多样化中的作用来解决。到目前为止，在所有已被研究的动物中，HOX基因簇负责确定身体前后轴线上的区域身份。这个基因簇的上游调控指向了身体计划之间形态差异的一个潜在来源。关于果蝇以外的HOX基因调控的知识是有限的。因此，特定的目的是在环节动物中鉴定已被证明调节HOX基因表达的苍蝇同源基因。将描述两个果蝇分段基因的同源基因，驼背和尾部，在水蚤和多毛类动物中。这种比较方法将使我们能够区分一般的发育机制和特定于门的机制，从而为环节动物胚胎的形成和区域规范提供新的见解。

0090378SavageCurrent understandings of cell differentiation and pattern formation in animals have largely been based on data obtained from 'model' systems such as the fruit fly Drosophila melanogastor. The extent to which developmental mechanisms operating in the fly are conserved in other phyla is at present unknown. This question will be addressed by examining annelid homologues of fly developmental regulatory genes and their role in the diversification of body plans. In all animals that have been studied to date, the Hox gene cluster is responsible for determining regional identity along the anterior-posterior body axis. The upstream regulation of this gene cluster points to a potential source of morphological variation between body plans. Knowledge of Hox gene regulation beyond Drosophila is limited. Therefore, the specific aim is to identify in annelids homologues to fly genes which have been shown to regulate Hox gene expression. The homologues to two Drosophila segmentation genes, hunchback and caudal , in both leeches and in polychaetes will be characterized. This comparative approach will allow us to differentiate between general developmental mechanisms and phylum-specific ones, in so doing providing novel insights into the formation and regional specification of the annelid embryo.