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Description
In the long history of life evolution, different species living in different environment developed the most adaptive
surviving mechanism for them under the selection pressure, among which some unmatchable become widly preserved in
different creatures, and the mechanism of replication is one of them. The majority of prokaryote share the same mechanism
of self-replication including DNA replication, chromosome seperation and cell division. These three parts comprised
the whole cell cycle, and the main model creature for researching the replication process is E.coli, which at the
same time is the main object of our project.
The replication process of E.coli replication can be devided into phase B,C and D, three phases. Phase B, also called
pre-replication phase, is for DNA replication proparation similar as G1 phase in eukaryote cell cycle. Phase C is
regarded as replication phase during which the chromosome is replicating corespond to the S phase in eukaryote. The
last phase, phase D, is called post-replication phase, in which the behave of chromosome seperation and cell division
happend just like what happened in G2 and M phase of eukaryote cells. the time of C phase and D phase in a generation
is relative constant, so what actually determines the cell cycle is the initiation of genome replication. We know
that cell have to garantee that each cell should have at least one chormosome, and this requires a highly coordination
between DNA replication and cell divsion. Though the delicate mechanism of the corrdination is still a puzzle, it
is clear that DnaA protein plays a significant role in this event. DnaA is a versatile protein, it can not only behave
like a helicase opening the duble-helix of replication initiation site, OriC, while have the function of raising
other proteins forming into the replisome to prolong the replication, but also can anchor the replicationg choromosome
on the cell membrane leading the following seperation of chromosome. But what makes it the linker between replication
and division is that its concentration determines the initiation volume of replication. So according to these information,
we think that regulating the combination of DNA and DnaA protein will be an efficient method to regulate cell replication.
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