POWRE: Genetic Regulatory Shifts in Insect Evolution

+昆虫胚胎发生的研究定义了两种主要的发育类型。大多数昆虫表现出一种短胚芽类型的发育，在这种发育过程中，胚芽雏形形成，并按顺序增加额外的节段。相比之下，长细菌类昆虫几乎同时沿着整个前后轴形成节段。这种行为被认为是起源的，部分原因是母体对材料和图案信息的贡献增加，并可能提供了快速早期发育的选择性优势。有人认为，调控的变化是通过一些胚胎模式机制从合子调控转变为母体调控而发生的。在果蝇这种长的生殖性昆虫中，几种基因产物是母体提供的，并被储存起来，直到需要特定的功能。然而，这些基因在其他昆虫中可能在多大程度上受到合子控制尚不清楚。果蝇FTZ转录因子1(FTZ-F1)基因是母系转录的。编码的蛋白质在胚胎中被翻译，是正常分割所必需的。在短小孢子甲中，FTZ-F1直系同源基因以胚胎配对条纹的形式表达。FTZ-F1控制从合子到母体的这种明显的转变可能为伴随着长胚胎发育的进化的调控变化提供了一个普遍的范式。或者，观察到的FTZ-F1的调控变化可能是该基因独有的。对其他几个具有母体效应的果蝇合子致死基因的Tribolium同源基因的分析将提供区分这些可能性所需的信息。POWRE提案中描述的研究代表了布朗博士的一条新的探索路线，并将提供机会，以实现晋升为正式研究教授所需的公认的独立性水平。

+Studies of insect embryogenesis have defined two major development types. Most insects display a short germ type of development in which a germ rudiment forms and additional segments are added sequentially. In contrast, long germ type insects form segments along the entire anterior-posterior axis virtually simultaneously. This behavior, thought to be derived, is due in part to an increased maternal contribution of materials and patterning information, and presumably offers the selective advantage of rapid early development. It has been suggested that regulatory changes occurred via a shift of some embryonic patterning mechanisms from zygotic to maternal regulation. In Drosophila, a long germ insect, several gene products are provided maternally and stored until required for specific functions. However, the extent to which these genes may be zygotically controlled in other insects is not known. The Drosophila gene ftz transcription factor 1 (ftz-f1) is maternally transcribed. The encoded protein is translated in the embryo and required for normal segmentation . In the short germ beetle, Tribolium castaneum, the ftz-f1 ortholog is expressed in embryonic pair-rule stripes. This apparent shift of ftz-f1 control from zygotic to maternal may provide a general paradigm for the regulatory changes which accompanied the evolution of long germ development. Alternatively, the regulatory change observed for ftz-f1 may be unique to this gene. Analysis of the Tribolium homologs of several other Drosophila zygotic lethal genes with maternal effects will provide the information necessary to distinguish between these possibilities. The research described in this POWRE proposal represents a new line of inquiry for Dr. Brown and will provide the opportunity to achieve a level of recognizable independence required for advancement to full Research Professor.