Most tumor cells,express MHC class I molecules on their surface, cytotoxic T cells can directly recognize tumor cells expressing neo-antigens.

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#Unit 3. Fundamental Processes

The GATC sites AT THE ORIGIN remain hemimethylated for 13 minutes after replication called as refractory period of replication cycle or delay time.

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#Unit 3. Fundamental Processes

At typical GATC sites elsewhere in the genome, remethylation begins immediately (1.5 minutes) following replication.

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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.