共 46 条
Suppression of chromosome segregation defects of Escherichia coli muk mutants by mutations in topoisomerase I
被引:133
作者:
Sawitzke, JA
[1
]
Austin, S
[1
]
机构:
[1] NCI, ABL Basic Res Program, Frederick Canc Res & Dev Ctr, Ft Detrick, MD 21702 USA
来源:
关键词:
D O I:
10.1073/pnas.030528397
中图分类号:
O [数理科学和化学];
P [天文学、地球科学];
Q [生物科学];
N [自然科学总论];
学科分类号:
07 ;
0710 ;
09 ;
摘要:
Escherichia coli muk mutants are temperature-sensitive and produce anucleate cells. A spontaneously occurring mutation was found in a Delta mukB::kan mutant strain that suppressed the temperature-sensitive phenotype and mapped in or near topA. the gene that encodes topoisomerase I. Previously characterized topA mutations, topA10 and topA66, were found to be general suppressors of muk mutants: they suppressed temperature sensitivity and anucleate cell production of cells containing null or point mutations in mukB and null mutations in mokE or mukF. The suppression correlated with excess negative supercoiling by DNA gyrase, and the gyrase inhibitor, coumermycin. reversed it. Defects in topA allow 99% of cell division events in muk null mutants to proceed without chromosome loss or loss of cell viability. This observation imposes important limitations on models for Muk activity and is consistent with a role for MukBEF in chromosome folding and DNA condensation.
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页码:1671 / 1676
页数:6
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