GENETIC ANALYSIS OF CELL CYCLE-DEPENDENT TRANSCRIPTION

细胞增殖受到复杂的控制， 其中之一是细胞内基因的差异表达， 周期 在芽殖酵母酿酒酵母中， 许多编码酶的基因的周期性转录 DNA合成所需的是细胞生长的先决条件 组蛋白基因转录的限制， 晚期G1-早期S期也可能进化为调节酵母 细胞周期 控制差速器的调节电路 将检测酵母组蛋白基因的转录。 影响细胞周期依赖性转录的调控突变 将通过筛选与以下疾病相关的表型来确定 组蛋白-lacZ融合基因的表达改变。 顺式 突变将被用来评估积极和消极的作用， 组蛋白启动子元件在周期性转录中的作用。 反式 突变导致在转录过程中的组成型转录， 细胞周期将确定所需的调控基因， 保持定期转录。 调控基因将 通过酵母突变体和克隆基因的互补克隆 将用于研究蛋白质的功能， 编码。

Cellular proliferation is subject to complex controls, one of which is the differential expression of genes during the cell cycle. In the budding yeast, Saccharomyces cerevisiae, the periodic transcription of a number of genes which encode enzymes required for DNA synthesis is a prerequisite for cells to progress through S-phase; the restriction of histone gene transcription to late G1-early S-phase may also have evolved to regulate the yeast cell cycle. The regulatory circuit which controls the differential transcription of the yeast histone genes will be examined. Regulatory mutations affecting cell cycle-dependent transcription will be identified by screening for phenotypes associated with the altered expression of histone-lacZ fusion genes. Cis-acting mutations will be used to assess the roles of positive and negative histone promoter elements in periodic transcription. Trans-acting mutations which result in constitutive transcription during the cell cycle will identify regulatory genes which are required to maintain periodic transcription. The regulatory genes will be cloned by complementation of yeast mutants and the cloned genes will be used to study the functions of the proteins which they encode.