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アクティブボード・２００２年 ３月
研究発表を行った学会；第２４回日本分子生物学会年会
２００１年１２月９日～１２日（横浜）
タイトル；Sister Chromosome Cohesion of Escherichia coli
発表者；砂子 由美
（発生医学研究センター 胚形成部門 細胞複製分野）
Abstract；
We analyzed Escherichia coli cells synchronized for initiation of chromosomal DNA replication by fluorescence in situ hybridization using fluorescent DNA probes corresponding to various chromosomal regions. Sister copies of regions in an approximately oriC-proximal half of the chromosome are cohesive with each other after replication until the late period of chromosome replication. Sister copies of regions relatively close to the terminus also are separated from each other in the same late period of replication. It is important that sister copies in all the tested regions are thus separated from each other nearly all at once in the late period of chromosome replication. These results are consistent with results obtained by FISH in randomly growing cultures. Cohesion of sister copies in an oriC-close region is observed in a dam null mutant lacking DNA adenine methyltransferase as same as in the parental isogenic dam+ strain, indicating that the cohesion is independent of DNA adenine methyltrasferase. This further implies that hemimethylated DNA binding proteins, such as SeqA, are not involved in the cohesion. On the other hand, the cohesion of sister copies of the oriC-close region was not observed in mukB null mutant cells, suggesting that MukB might be involved in the chromosome cohesion.
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