MBIO 4440 Lecture 7: Cell Division and Replication
30 Jan 2019
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A refresher on chromosome replication and cell division. Remember that the septum forms at the division site where the ftsz protein (ftsz ring) is located. Each daughter cell receives one parental and one newly synthesized strand: replication of cellular dna is semiconservative, replication in bacteria begins at a single origin (oric), after initiation, a replication bubble forms. Contains two replication forks that move in opposite directions around the chromosome: replication ends at defined termination (ter) sites located opposite to the origin. Recall: dnaa, dnab (helicase, dnac (loader, dna polymerase iii, clamp and sliding clamp, dna primase, single stranded dna binding protein, rnase h, dna ligase, okasaki fragments, oric, ter. Review of initiation of replication ii: the start of dna replication is precisely timed and linked to the ratio of dna to cell mass. In e. coli, dnaa accumulates during growth, and then triggers the initiation of replication. Dnaa-atp complexes bind to 9-bp repeats upstream of the origin.
