CIL:39583, Saccharomyces cerevisiae. In Cell Image Library

A time lapse experiment of Saccharomyces cerevisiae expressing GFP tagged Lte1. LTE1 is essential for termination of M phase at low temperatures, along with TEM1, and CDC15, all part of the mitotic exit network which is an elaborate signaling system comprising at least eight essential genes: CDC5, CDC14, CDC15, DBF2, DBF20, LTE1, MOB1, and TEM1. LTE1 was originally discovered as a locus essential for growth at 8 C, and was named for this trait as Low Temperature Essential 1. It was later inferred from sequence similarities that LTE1 must code for a guanine nucleotide exchange factor. Genetic evidence suggests that Lte1p activates the GTPase Tem1p which activates the protein kinase Cdc15p. Cdc15p then relieves the inhibition of the protein phosphatase Cdc14p by Net1p, thereby allowing exit from mitosis. In a normal cell cycle, Bub2p bound to Tem1p restrains mitotic exit until the daughter-bound centrosome (with which both Bub2p and Tem1p preferentially associate) comes into contact with Lte1p in the bud, effectively coupling mitotic exit with nuclear segregation. Some evidence suggests that the spatial separation of Tem1p and Lte1p is a key mechanism for controlling the timing of mitotic exit. These phase,gfp z-series images are part of an image group that ranges from CIL:39581-39585. Note that there are additional groups showing time series of other cell cycle regulation proteins by the same authors in the Library.

本数据集为表达绿色荧光蛋白（Green Fluorescent Protein, GFP）标记的Lte1蛋白的酿酒酵母（Saccharomyces cerevisiae）延时实验样本。LTE1（Low Temperature Essential 1）与TEM1、CDC15共同参与低温环境下M期（有丝分裂期）的终止过程，三者均属于有丝分裂退出网络（mitotic exit network, MEN）——该精密信号系统至少包含8个必需基因：CDC5、CDC14、CDC15、DBF2、DBF20、LTE1、MOB1与TEM1。LTE1最初作为8℃条件下生长必需的基因座被发现，并据此特性命名为低温度必需基因1。后续通过序列同源性分析推断，LTE1编码一种鸟苷酸交换因子（guanine nucleotide exchange factor, GEF）。遗传学实验证据表明，Lte1p可激活GTP酶Tem1p，而Tem1p继而激活蛋白激酶Cdc15p；Cdc15p随后解除Net1p对蛋白磷酸酶Cdc14p的抑制作用，最终促成细胞退出有丝分裂。在正常细胞周期中，结合于Tem1p的Bub2p会抑制有丝分裂退出，直至与Bub2p和Tem1p优先结合的子代中心体与芽体中的Lte1p发生接触，从而将有丝分裂退出与核分离过程紧密偶联。已有研究提示，Tem1p与Lte1p的空间分隔是调控有丝分裂退出时序的核心机制。本研究的相衬及GFP标记的Z轴序列（z-series）图像隶属于编号为CIL:39581-39585的图像组。需注意，该图像库中另有同一研究团队制作的其他细胞周期调控蛋白的时间序列图像数据集。