Cell Aggregation & Differentiation is common to all Dictyostelids.

It consists of an interconnected programme of cell movement and cell differentiation.

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#Unit 3. Fundamental Processes

One other region behaves like oriC:

The promoter of the dnaA gene also shows a delay before remethylation begins.

While it is hemimethylated, the dnaA promoter is repressed, which causes a reduction in the level of DnaA protein.

So Initiation of Replication (E.coli) takes place when GATC at origin is full methylated as well as promoter of DnaA gene. 

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#Unit 3. Fundamental Processes

An unmethylated CG site remains unmethylated after replication.

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#Unit 3. Fundamental Processes

DnaA is the E. coli licensing factor that must be made anew for each round of replication. Drugs that block protein synthesis block a new round of replication, but not continuation of replication.

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#Unit 3. Fundamental Processes

DnaA is an ATP-binding protein.

The first stage in initiation is binding of the DnaA-ATP protein complex to the fully methylated oriC sequence.

This takes place in association with the inner membrane. DnaA is in the active form only when bound to ATP.

DnaA has intrinsic ATPase activity that hydrolyzes ATP to ADP and thus inactivates itself when the initiation stage ends.

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#Unit 3. Fundamental Processes

DnaA ATPase activity is stimulated by membrane phospholipids and single-stranded DNA.

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#Unit 3. Fundamental Processes

DnaA-ATP in an extended multimeric state promoted by the accessory protein DiaA, which stimulates cooperative binding of DnaA.

DnaA-ATP binds cooperatively to form a helical central core around which oriC DNA is wrapped.