MOLECULAR GENETICS OF GENE DOSAGE COMPENSATION AND SEX

基因剂量补偿和性别的分子遗传学

• 批准号: 3466276
• 负责人: ALAN C CHRISTENSEN
• 金额: $ 9.75万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3466276
• 关键词: Drosophilidae; autoradiography; complementary DNA; cytogenetics; developmental genetics; endonuclease; gel electrophoresis; gene dosage; gene expression; gene interaction; gene mutation; genetic manipulation; genetic promoter element; genetic regulation; genetic transcription; genetic translation; molecular cloning; molecular genetics; nucleic acid hybridization; nucleic acid probes; phosphogluconate dehydrogenase; sex chromosomes; sex determination

In Drosophila sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. Cells with one X chromosome and two sets of automsomes are males and cells with 2 X chromosomes and two sets of autosomes are females. Since males have the same requirements for X-linked gene products as females, they respond by hyperactivating the X chromosome at the transcriptional level to compensate for the difference in gene dosage. This project is aimed at two questions: how do male cells double the transcription rate of virtually every gene on the X chromosome, and how do cells count the number of X chromosomes. The first question will be addressed by using the gene for 6-phosphogluconate dehydrogenase (Pgd) as a model gene for the X chromosome. In vitro manipulation of the gene and its promoter, followed by reintegration into the Drosophila genome, will be used to find the cis-acting regulatory site of the Pgd gene that is responsible for the dosage compensation response. Dosage compensation is an important topic in the study of gene regulation since it changes the expression levels of a large battery of genes by exactly two-fold. This subtle regulation may be controlled by a novel mechanism, or by novel application of conventional mechanisms. Understanding dosage compensation will be an important step in understanding the coordinated regulation of a large group of genes, which is also a significant facet of development and neoplasia. The question of how the X chromosomes are counted will be attacked by cloning the Tp1 gene either by a chromosome walk or transposon tagging, and then studying the expression of the gene. Tpl is a locus on chromosome 3 which is extremely dosage sensitive. Drosophila requires exaclty 2 doses of Tpl for survival. Individuals bearing 1 or 3 doses die as embryos. It has been suggested that Tpl is involved in counting the X chromosomes for two reasons. One would expect a gene that titrates the X chromosomes against itself to be dosage sensitive, and in addition, Tpl appears to interact with the X in aneuploids. If this hypothesis turns out be incorrect, then Tpl must perform a vital function in embryogenesis or cellular metabolism. In either case the study of Tpl has for-reaching implications for sex determination, the consequences of aneuploidy, and embryogenesis. Drosophila is one of very few organisms in which such a gene can be studied since it has a dominant lethal phenotype.

果蝇的性别是由 X 数量的比率决定的 染色体与常染色体组的数量。 细胞有一个 X染色体和两组常染色体是男性和细胞 具有 2 条 X 染色体和两组常染色体的女性。 由于男性对X连锁基因有相同的要求 作为女性，她们通过过度激活 X 来做出反应 染色体在转录水平上进行补偿 基因剂量的差异。 该项目旨在解决两个问题： 雄性细胞如何使几乎所有细胞的转录率加倍 X染色体上的基因，以及细胞如何计算X染色体的数量 X 染色体。 第一个问题将通过使用 6-磷酸葡萄糖酸脱氢酶（Pgd）基因作为模型基因 对于 X 染色体。 基因及其体外操作 启动子，然后重新整合到果蝇基因组中， 将用于寻找 Pgd 基因的顺式作用调控位点 它负责剂量补偿反应。 剂量 补偿是基因调控研究的一个重要课题 因为它改变了大量基因的表达水平 正好两倍。 这种微妙的调节可能是由 一种新颖的机制，或通过传统的新颖应用 机制。 了解剂量补偿将是一个 理解协调监管的重要一步 一大群基因，这也是一个重要的方面 发育和瘤形成。 X如何的问题 计数的染色体将受到克隆 Tp1 的攻击 通过染色体行走或转座子标记的基因，然后 研究基因的表达。 Tpl是染色体上的一个位点 3 对剂量极其敏感。 果蝇需要 精确 2 剂 Tpl 才能存活。 携带 1 或 3 的个人 剂量作为胚胎死亡。 有人建议 Tpl 参与其中 计算 X 染色体有两个原因。 人们会期望一 滴定 X 染色体自身剂量的基因 敏感，此外，Tpl 似乎与 X 相互作用 非整倍体。 如果这个假设被证明是不正确的，那么 Tpl 必须在胚胎发生或细胞中发挥重要作用 代谢。 无论哪种情况，Tpl 的研究都有深远的意义。 对性别决定的影响，后果 非整倍性和胚胎发生。 果蝇是极少数的一种 可以在其中研究这种基因的生物体，因为它具有 显性致死表型。