Regulation Of Cellular Proliferation And Diversity In Drosophila

果蝇细胞增殖和多样性的调节

基本信息

批准号：
8736831
负责人：
JAMES A. KENNISON
金额：
$ 66.52万
依托单位：
EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8736831
关键词：
Adult Beryllium Binding Biological Assay Biological Models Cancer Etiology Cell Fate Control Cell Proliferation Cells Chromatin Remodeling Factor Cis-Acting Sequence Comb animal structure Cues DNA Defect Development Developmental Gene Disease Drosophila genome Drosophila genus Ectopic Expression Embryo Fertility Gene Expression Regulation Gene Targeting Genes Genetic Genetic Enhancer Element Genetic Transcription Genome Genomics Goals Head Homeobox Genes Homologous Gene Human Human Development Lead Maintenance Male Infertility Male Sterility Mitotic Molecular Genetics Mutation Organism Pattern Polycomb Proteins Proteome Regulation Regulator Genes Regulatory Element Regulatory Pathway Reporter Genes Repression Role Specific qualifier value Staging Structure Tissues Trans-Activators Transcriptional Silencer Elements Transforming Growth Factor beta Transgenes Work brahma fly gene function homeodomain human disease male man sex tool transcription factor ubiquitin-protein ligase

项目摘要

One goal of the Section on Drosophila Gene Regulation is to understand the regulation of homeotic gene function in Drosophila. The homeotic genes encode homeodomain-containing transcription factors that control cell fates by regulating the transcription of downstream target genes. The homeotic genes are expressed in precise spatial patterns that are crucial for the proper determination of segmental identities. Trans-acting factors required for the expression or function of the homeotic genes are encoded by the trithrorax group genes. We have shown that the protein encoded by the trithorax group gene tonalli is probably a SUMO-E3 ligase required for the sumoylation of the brahma chromatin remodeling complex and possibly other transcription factors. Cis-acting transcriptional regulatory elements from the homeotic genes have been previously-identified by assays in transgenes in Drosophila. These assays have identified both tissue-specific enhancer elements, as well as cis-regulatory elements that are required for the maintenance of activation or repression throughout development. While these transgene assays have been important in defining the structure of the cis-regulatory elements and identifying trans-acting factors that bind them, their functions within the contexts of the endogenous genes is still not well understood. Using a transgene assay, we have identified five candidate fragments of DNA from the Sex combs reduced gene that cause transcriptional silencing of a reporter gene. These cis-regulatory silencing elements require the trans-acting proteins encoded by the Polycomb group genes. Genetic studies first identified the Polycomb group genes by their defects in transcriptional silencing of the homeotic genes. To identify new Polycomb group genes, we have developed a transgene assay using the cis-regulatory silencing elements from the Sex combs reduced homeotic gene. Recessive mutations that disrupt transgene silencing are recovered in mitotic clones in heterozygous flies. We have screened about 60% of the genome and isolated mutations in all of the known Polycomb group genes in the genomic regions screened. We have also isolated mutations in several new Polycomb group genes. To understand the downstream regulatory role of the homeotic genes, we have characterized a cis-regulatory element within a homeotic target gene. This element is required for proper expression of one of the Drosophila TGF-beta homologs in the cells that form the adult head structures. Genetic defects that cause male infertility are common in both man and Drosophila. We have shown that mutations to male sterility in Drosophila are about 15% as common as mutations to lethality, suggesting that a substantial proportion of the Drosophila genome may be required only for male fertility. As expected from these results, we have also found that as much as 20-25% of the Drosophila proteome may be expressed only in males.

有关果蝇基因调节的部分的一个目标是了解果蝇中同源基因功能的调节。同源基因编码含同源域的转录因子，这些因子通过调节下游靶基因的转录来控制细胞的命运。同源基因以精确的空间模式表达，这对于适当确定分段身份至关重要。同源基因表达或功能所需的跨作用因子由Trithrorax组基因编码。我们已经表明，由Trithorax组基因Tonalli编码的蛋白质可能是SUMO-E3连接酶用于梵天染色质重塑复合物以及可能其他转录因子所需的SUMO-E3连接酶。从果蝇中的转基因中的测定，来自同源基因的顺式转录调节元件已被先前鉴定出来。这些测定方法已经确定了组织特异性增强子元素以及在整个发育过程中维持激活或抑制所必需的顺式调节元件。尽管这些转基因测定对于定义顺式调节元件的结构并识别结合它们的跨性因子的结构很重要，但在内源基因的背景下它们的功能仍未得到很好的了解。使用转基因测定法，我们从性爱梳中鉴定了五个DNA的候选片段，从而减少了导致报告基因转录沉默的基因。这些顺式调节的沉默元件需要由多肉体基因编码的跨作用蛋白。遗传学研究首先通过其在同源基因的转录沉默中的缺陷来鉴定了多肉液基因。为了鉴定新的PolyComb基因，我们使用了来自性别梳子的顺式调节沉默元件，开发了一个转基因测定，从而减少了同源基因。破坏转基因沉默的隐性突变在杂合蝇中有丝分裂克隆中回收。我们已经在筛选的基因组区域中所有已知的多角膜基因基因中筛选了大约60％的基因组和分离突变。我们还在几个新的PolyComb基因基因中分离了突变。为了了解同源基因的下游调节作用，我们表征了同源靶基因内的顺式调节元件。在形成成人头部结构的细胞中，需要正确表达果蝇TGF-β同源物之一，需要此元素。导致男性不育症的遗传缺陷在人和果蝇中都是常见的。我们已经表明，果蝇中男性无菌性的突变大约与致死性突变一样普遍，这表明只有男性生育能力可能需要很大一部分果蝇基因组。从这些结果中预期，我们还发现，果蝇蛋白质组的20-25％只能在男性中表达。