CELL CYCLE CONTROL IN EARLY DROSOPHILA DEVELOPMENT

果蝇早期发育中的细胞周期控制

• 批准号: 2397617
• 负责人: Terry L. ORR-WEAVER
• 金额: $ 20.66万
• 依托单位: WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2397617
• 关键词: DNA replication; Drosophilidae; alleles; antibody; cell cycle; cell growth regulation; cyclins; developmental genetics; early embryonic stage; fertilization; gene expression; gene mutation; immunoprecipitation; invertebrate embryology; laboratory rabbit; laboratory rat; mass spectrometry; meiosis; molecular cloning; northern blottings; oogenesis; protein structure function; regulatory gene; western blottings

The regulation of DNA replication in multicellular organisms is critical for their development. In addition, the improper regulation of DNA replication can lead to disease states such as malignancy or cell death. The experiments in this proposal address two aspects of the developmental regulation of DNA replication. One of the earliest controls in development is the restart of DNA replication in the embryo in response to fertilization. In most organisms the control of DNA replication in altered in some of the cells such that S phase becomes unlinked from mitosis and cell division, leading to an increase in the DNA content of the cell (polyteny or polyploidy). These two aspects of the developmental regulation of DNA replication will be investigated in the fruit fly, Drosophila melanogaster, because mutations can be isolated in which DNA replication is improperly controlled. Two genes have been identified, plutonium (plu) and pan gu (png), that regulate DNA replication at the onset of development. Unfertilized eggs mutant in either of these genes inappropriately undergo extensive DNA replication; moreover, the DNA in all four meiotic products appears to replicate rather than simply the pronucleus. Analysis of plu and png will be key to understanding how a resting oocyte is converted into a developing embryo in response to maturation and fertilization signals. The mechanisms by which plu and png regulate DNA replication in early development will be elucidated by experiments that will determine whether they control entry into S phase or whether they regulate DNA replication within S phase, possibly by blocking reinitiation. The products encoded by the plu and png genes will be identified by cloning the genes, and their cellular location will be determined. The developmental expression of the genes will be addressed, particularly whether the gene products are altered after fertilization. The interaction between plu, png, and four other genes that regulate the earliest cell cycles of development will be investigated by genetic and molecular approaches. Polytenization in Drosophila results from a modified cell cycle, the endo cell cycle, in which S phase alternates with a gap phase, but no mitosis occurs. The endo cell cycle is under developmental control because the onset of polytenization occurs with precise temporal and spatial regulation during the latter half of embryogenesis. Regulatory genes that trigger the onset of polytenization in development or that control the endo cell cycle will be identified and analyzed. Candidate regulatory genes have been isolated by the criteria that they are transcriptionally activated at the onset of polytenization in several tissues in the embryo. The effect of mutation of these genes on polytenization will be determined, and those that are shown to regulate this process will be cloned. A selection will be done for mutants in which polytenization is affected.

多细胞生物中 DNA 复制的调控至关重要 为了他们的发展。 此外，DNA调控不当 复制可能导致疾病状态，例如恶性肿瘤或细胞死亡。 本提案中的实验涉及发育的两个方面 DNA复制的调节。 最早的控制之一 发育是胚胎中 DNA 复制的重新启动作为响应 来受精。 在大多数生物体中，DNA 复制的控制 一些细胞发生改变，使得 S 期与 有丝分裂和细胞分裂，导致DNA含量增加 细胞（多线性或多倍体）。 这两个方面 DNA复制的发育调控将在 果蝇，黑腹果蝇，因为突变可以在 DNA 复制受到不当控制。 已鉴定出两个基因：钚 (plu) 和盘古 (png)， 在发育开始时调节 DNA 复制。 未受精的鸡蛋 这些基因中的任何一个的突变体不恰当地经历了广泛的DNA 复制；此外，所有四种减数分裂产物中的 DNA 似乎 复制而不是简单地复制原核。 plu和png分析 将是了解静息卵母细胞如何转化为卵母细胞的关键 发育中的胚胎响应成熟和受精信号。 plu和png在早期调控DNA复制的机制 发展将通过实验来阐明，这些实验将确定是否 它们控制进入 S 期或是否调节 DNA 复制 在 S 期内，可能通过阻止重新启动。 产品编码 plu和png基因将通过克隆基因来识别，并且 他们的蜂窝位置将被确定。 发展表现 将解决基因的问题，特别是基因产物是否 受精后发生改变。 plu、png 和 之间的交互 其他四个调节最早细胞发育周期的基因 将通过遗传和分子方法进行研究。 果蝇中的多聚化是由细胞周期改变引起的，即内切酶 细胞周期，其中 S 期与间隙期交替，但没有有丝分裂 发生。 内细胞周期处于发育控制之下，因为 多聚化的开始发生在精确的时间和空间上 胚胎发生后半期的调控。 调控基因 触发发育中多聚化的开始或控制 内细胞周期将被识别和分析。 候选人 调节基因已根据其标准被分离出来 在多聚化开始时转录被激活 胚胎中的组织。 这些基因突变的影响 多聚化将被确定，并且那些被证明可以调节的 该进程将被克隆。 将对突变体进行选择 其多聚化受到影响。