POLYCOMB GROUP GENES AND GENE REGULATION

果蝇Zest[E(Z)]基因增强子与黑腹果蝇有关 在发育过程中的多个基因抑制的例子中。第一 被鉴定为玉米1-白(z-w)的主要函数增益修饰剂 相互作用时，突变的E(Z)等位基因也会产生同源异型转化。 E(Z)活性的降低导致z-w的抑制 猪细小病毒片段识别基因的相互作用和异位表达 触角线虫和双胸虫基因复合体。后一种效应定义了E(Z) 作为基因聚合组的一员。无论是母性的还是 合子产生的E(Z)活性是正确调节 胚胎和想象发育过程中的片段同一性基因。完成 缺乏合子产生的E(Z)活性会导致细胞堵塞 幼虫神经母细胞的增殖和染色体的破坏 组织。因此，E(Z)的减少似乎干扰了 多个基因抑制的例子，而它的完全缺失阻止了 细胞增殖并破坏染色体组织。因此， 通过分子和生化分析E(Z)蛋白的活性， 在基因调控和高阶染色质组织之间可能 已澄清。这项工作的长期目标是了解 E(Z)产物的分子机制，以及其他 多梳状基因，执行其基因定义的功能。这个 这项提议的具体目标是利用多方面的方法 包括遗传、分子、免疫和生化工具，以(1) 确定E(Z)蛋白的亚细胞和内定位 整个生物体，(2)阐明其分子机制(S)。 抑制转录，以及(3)剖析E(Z)的功能结构域。 蛋白。将采取的方法包括(1)使用特异性抗体 用于E(Z)蛋白确定其定位，(2)使用这些相同的 用抗体检测病毒在体外和体内的相互作用 E(Z)蛋白与已鉴定的调控DNA序列 作为E(Z)活性的靶点，并与其他基因的产物一起 已被遗传证明与E(Z)相互作用，以及(3)DNA序列 已有突变E(Z)等位基因的分析及体外构建 基因的改变形式，然后将在体外和 将其导入果蝇胚系，并在体外和体内进行检测 活体活动。基因表达的错误调控一直是 与多种疾病有关，包括各种癌症。在漫长的岁月里 术语，更好地理解基因调控的机制 更高阶染色体组织的潜在作用将是 对了解和治疗此类疾病至关重要。

The Enhancer of zeste [E(z)] locus of Drosophila melanogaster is implicated in multiple examples of gene repression during development. First identified as dominant gain-of-function modifiers of the zeste1-white (z-w) interaction, mutant E(z) alleles also produce homeotic transformations. Reduction of E(z)+ activity leads to both suppression of the z-w interaction and ectopic expression of segment identity genes of the Antennapedia and bithorax gene complexes. This latter effect defines E(z) as a member of the Polycomb-group of genes. Both maternally and zygotically produced E(z)+ activity is required to correctly regulate the segment identity genes during embryonic and imaginal development. Complete lack of zygotically produced E(z) activity results in blockage of cell proliferation in larval neuroblasts, and disruption of chromosome organization. Thus, it seems that reduction of E(z)+ interferes with multiple examples of gene repression, and that its complete absence blocks cell proliferation and disrupts chromosome organization. Therefore, through molecular and biochemical analysis of E(z) protein activity, a link between gene regulation and higher order chromatin organization may be elucidated. The long term goal of this work is to gain an understanding of the molecular mechanisms by which the E(z) product, and those of other Polycomb-group genes, carry out their genetically defined functions. The specific aims of this proposal are to utilize a multifaceted approach including genetic, molecular, immunological and biochemical tools to (1) determine the localization of the E(z) protein, both subcellular and within the whole organism, (2) elucidate the molecular mechanism(s) by which it represses transcription, and (3) dissect the functional domains of the E(z) protein. The approaches to be taken include (1) use of antibodies specific for the E(z) protein to determine its localization, (2) use of these same antibodies to examine potential in vitro and in vivo interactions of the E(z) protein both with regulatory DNA sequences that have been identified as targets for E(z) activity, and with the products of other genes that have been genetically shown to interact with E(z), and (3) DNA sequence analysis of existing mutant E(z) alleles, and in vitro construction of altered forms of the gene, which will then be both expressed in vitro and introduced into the Drosophila germ line and assayed for in vitro and in vivo activities, respectively. Misregulation of gene expression has been implicated in a number of diseases, including various cancers. In the long term, a better understanding of the mechanisms by which genes are regulated and the potential role of higher order chromosome organization will be crucial to understanding and treating such diseases.