Growth in cell length in the fission yeast Schizosaccharomyces pombe.
Growth in cell length in the fission yeast Schizosaccharomyces pombe.
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发表时间：
1985-04
影响因子：
4
通讯作者：
J. Mitchison;P. Nurse
中科院分区：
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作者：
J. Mitchison;P. Nurse
裂殖酵母的圆柱形细胞的长度是在末端而不是中部伸长的。在细胞周期的开始阶段，生长被限制在前一个周期中存在的“老端”。之后，从隔膜形成的“新末端”开始生长，这一点我们称之为内托(“新末端起飞”)。硫代荧光素染色细胞的荧光显微镜已被用来研究大小突变体、阻断的CDC突变体以及不同生长温度和介质中的Neto。在野生型细胞(菌株972)中，Neto发生在周期的0.34处，细胞长度为9.5微米。对于分裂时较小的大小突变体，Neto发生在相同大小(9.0-9.5微米)，但这直到周期的后期才能实现。另一个对照在更大的突变体中操作，因为Neto发生在与野生型相同的周期阶段(约0.32)，但细胞尺寸更大。这种控制可能是在G2早期完成一个事件的必要条件，因为在周期的这一点之前被阻止的大多数CDC突变细胞都不显示内毒素，而在G2晚期被阻止的大多数细胞确实显示了它。我们得出结论，只有当(1)细胞长度大于9.0-9.5微米的临界值；(2)细胞已经穿过周期的第一个0.3-0.35并通过早期G2时，才会发生Neto。在较差的介质中，Neto被延迟，在这种介质中，细胞大小也会减小。在稳态条件下，温度对NETO的影响很小，但在温度变化后会有几个小时的瞬时延迟。内托后来感染了另一种野生型病毒132。用时移显微照相技术跟踪单个细胞的长度生长率。野生型细胞在周期的前75%表现出两个线形片段。有一个速率变化点(RCP)，与Neto一致，全长延长率增加35%。这一增长不仅仅是因为新端生长的开始，因为在RCP的一些单元中，旧端生长放缓了。Cdc 11.123是一个突变体，其分离和分裂在35摄氏度时被阻止，但核分裂仍在继续。
The cylindrical cells of Schizosaccharomyces pombe grow in length by extension at the ends and not the middle. At the beginning of the cell cycle, growth is restricted to the 'old end', which existed in the previous cycle. Later on, the 'new end', formed from the septum, starts to grow at a point in the cycle that we have called NETO ('new end take-off'). Fluorescence microscopy on cells stained with Calcofluor has been used to study NETO in size mutants, in blocked cdc mutants and with different growth temperatures and media. In wild-type cells (strain 972) NETO happens at 0.34 of the cycle with a cell length of 9.5 microns. With size mutants that are smaller at division, NETO takes place at the same size (9.0-9.5 microns) but this is not achieved until later in the cycle. Another control operates in larger size mutants since NETO occurs at the same stage of the cycle (about 0.32) as in wild type but at a larger cell size. This control is probably a requirement to have completed an event in early G2, since most cdc mutant cells blocked before this point in the cycle do not show NETO whereas most of those blocked in late G2 do show it. We conclude that NETO only happens if: (1) the cell length is greater than a critical value of 9.0-9.5 microns; and (2) the cell has traversed the first 0.3-0.35 of the cycle and passed early G2. NETO is delayed in poor media, in which cell size is also reduced. Temperature has little effect on NETO under steady-state conditions, but there is a transient delay for some hours after a temperature shift. NETO is later in another wild-type strain, 132. Time-lapse photomicrography was used to follow the rates of length growth in single cells. Wild-type cells showed two linear segments during the first 75% of the cycle. There was a rate-change point (RCP), coincident with NETO, where the rate of total length extension increased by 35%. This increase was not due simply to the start of new-end growth, since old-end growth slowed down in some cells at the RCP. cdc 11.123 is a mutant in which septation and division is blocked at 35 degrees C but nuclear division continues.(ABSTRACT TRUNCATED AT 400 WORDS)