酿酒酵母有丝分裂过程中染色单体的随机分离。
Random segregation of chromatids at mitosis in Saccharomyces cerevisiae.
作者信息
Neff M W, Burke D J
机构信息
Department of Biology, University of Virginia, Charlottesville 22901.
出版信息
Genetics. 1991 Mar;127(3):463-73. doi: 10.1093/genetics/127.3.463.
Previous experiments suggest that mitotic chromosome segregation in some fungi is a nonrandom process in which chromatids of the same replicative age are destined for cosegregation. We have investigated the pattern of chromatid segregation in Saccharomyces cerevisiae by labeling the DNA of a strain auxotrophic for thymidine with 5-bromodeoxyuridine. The fate of DNA strands was followed qualitatively by immunofluorescence microscopy and quantitatively by microphotometry using an anti-5-bromodeoxyuridine monoclonal antibody. Chromatids of the same replicative age were distributed randomly to daughter cells at mitosis. Quantitative measurements showed that the amount of fluorescence in the daughter nuclei derived from parents with hemilabeled chromosomes diminished in intensity by one half. The concentration of 5-bromodeoxyuridine used in the experiments had little effect on the frequency of either homologous or sister chromatid exchanges. We infer that the 5-bromodeoxyuridine was distributed randomly due to mitotic segregation of chromatids and not via sister chromatid exchanges.
先前的实验表明，某些真菌中的有丝分裂染色体分离是一个非随机过程，其中相同复制年龄的染色单体注定会共同分离。我们通过用5-溴脱氧尿苷标记对胸苷营养缺陷型菌株的DNA，研究了酿酒酵母中染色单体分离的模式。通过免疫荧光显微镜定性地追踪DNA链的命运，并使用抗5-溴脱氧尿苷单克隆抗体通过显微光度法进行定量。相同复制年龄的染色单体在有丝分裂时随机分配到子细胞中。定量测量表明，来自具有半标记染色体的亲本的子核中的荧光量强度降低了一半。实验中使用的5-溴脱氧尿苷浓度对同源或姐妹染色单体交换的频率影响很小。我们推断，5-溴脱氧尿苷是由于染色单体的有丝分裂分离而随机分布的，而不是通过姐妹染色单体交换。
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