تسجيل الدخول

تسجيل

DNA Replication:- Bacterial Replication Is Organized in Membrane Bound Replication Factories

المؤلف:  David L. Nelson، Michael M. Cox

المصدر:  Lehninger Principles of Biochemistry

الجزء والصفحة:  p963-964

2026-07-20

56

DNA Replication:- Bacterial Replication Is Organized in Membrane Bound Replication Factories

The replication of a circular bacterial chromosome is highly organized. Once bidirectional replication is initiated at the origin, the two replisomes do not travel away from each other along the DNA. Instead, the replisomes are linked together and tethered to one point on the bacterial inner membrane, and the DNA substrate is fed through this “replication factory” (Fig. 25–18a). The tethering point is at the center of the elongated bacterial cell. After initiation, each of the two newly synthesized replication origins is partitioned into one half of the cell, and continuing replication extrudes each new chromosome into that half (Fig. 25–18b). The elaborate spatial organization of the newly replicated chromo somes is orchestrated and maintained by many proteins, including bacterial homologs of the SMC proteins and topoisomerases . Once replication is terminated, the cell divides, and the chromosomes sequestered in the two halves of the original cell are accurately partitioned into the daughter cells. When replication commences in the daughter cells, the origin of replication is sequestered in new replication factories formed at a point on the membrane at the center of the cell, and the entire process is repeated.