CONTROL OF CELL TYPE AND GAMETOGENESIS

细胞类型和配子发生的控制

• 批准号: 3269865
• 负责人: JAMES E HABER
• 金额: $ 18.77万
• 依托单位: BRANDEIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1976
• 资助国家: 美国
• 起止时间: 1976-01-01 至 1991-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3269865
• 关键词: Saccharomyces; alleles; cell cycle; cell differentiation; cell transformation; cell type; cytogenetics; endonuclease; fungal genetics; gene complementation; gene conversion; gene expression; gene mutation; genetic manipulation; genetic mapping; genetic markers; genetic recombination; meiosis; messenger RNA; microscopy; molecular cloning; molecular genetics; mutagens; nucleic acid hybridization; nucleic acid sequence; radiotracer; ribosomal RNA; sporogenesis; temperature sensitive mutant

The mating type (MAI) genes of Saccharomyces cerevisiae are part of a complex network of genetic and physiological controls of cell type, cell lineage, and differentiation. The expression of the MAT genes themselves involves their activation by transposition from a silent copy, or donor, locus to the MAT locus, where either a or Alpha information is expressed. The work that we have proposed is designed to understand the mechanism by which MAT genes are transposed. The homothallic switching of MAT genes is a substitution/recombination event in which a copy of a of Alpha sequences at HML or HMR is used to replace the information at MAT. This gene conversion process is initiated by a site-specific endonuclease, but the molecular mechanism by which strands are transferred is not known. One major goal of this project is to define the molecular events occurring during this transposition process, to identify and characterize intermediates of the reaction and to define what DNA sequences at MAT and the donor loci are required for this process. In this regard, the project also seeks to determine in what ways the switching of MAT genes is similar to other mitotic recombination events. A second major goal of this project is to understand how the MAT locus interacts with the donor loci. Little is understood about the ways that distant sequences can be brought together efficiently to participate in a recombination event. When MATa cells switch, they preferentially interact with the donor HML, on the left arm of the same chromosome, while MATAlpha cells selectively pair with HMR. DNA sequences adjacent to MAT that affect this pairing will be characterized, as will mutations that affect the normal donor preference. The ability of cells to undergo meiosis depends both on the presence of MATa and MATAlpha alleles and on physiological signals. Experiments are also proposed to characterize a large class of mutations in 22 genes that affect normal G1 cell cycle arrest when cells are starved for amino acids or grown to stationary phase (and are thus unable to sporulate). Preliminary experiments have suggested that these mutations affect a network of genes that affect protein synthesis, amino acid biosynthesis and cell cycle arrest.

酿酒酵母的交配型 (MAI) 基因是 细胞类型、细胞的遗传和生理控制的复杂网络 血统和分化。 MAT基因本身的表达 涉及通过从沉默副本或供体转座来激活它们， 轨迹到 MAT 轨迹，其中表达 a 或 Alpha 信息。 我们提出的工作旨在通过以下方式理解该机制： 哪些 MAT 基因被转座。 MAT 基因的同宗转换是 替换/重组事件，其中α序列的副本 HML 或 HMR 中的信息用于替换 MAT 中的信息。 这个基因 转化过程是由位点特异性核酸内切酶启动的，但 链转移的分子机制尚不清楚。 一 该项目的主要目标是定义发生的分子事件 在这个换位过程中，识别和表征 反应的中间体并定义 MAT 和 处的 DNA 序列 该过程需要供体基因座。 对此，该项目 还试图确定 MAT 基因的转换在哪些方面是相似的 其他有丝分裂重组事件。 该项目的第二个主要目标 目的是了解 MAT 基因座如何与供体基因座相互作用。 小的 了解如何将遥远的序列组合在一起 有效地参与重组事件。 当 MATa 细胞 开关时，它们优先与供体 HML 相互作用，位于左臂上 相同的染色体，而 MATAlpha 细胞选择性地与 HMR 配对。 脱氧核糖核酸 影响该配对的与 MAT 相邻的序列将被表征， 影响正常捐赠者偏好的突变也会如此。 细胞进行减数分裂的能力取决于是否存在 MATa 和 MATAlpha 等位基因和生理信号。 实验是 还提出表征 22 个基因中的一大类突变，这些突变 当细胞缺乏氨基酸时影响正常的 G1 细胞周期停滞 或生长至静止期（因此无法形成孢子）。 初步实验表明这些突变影响 影响蛋白质合成、氨基酸生物合成和 细胞周期停滞。