CH391L/S12/Origins of Replication
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Origins of Replication
This is an expansive, convoluted, and poorly documented field. Feel free to chime in, Adam
Modes of replication
Rolling circle
Strand displacement
Theta
Incompatibility Groups
- ColE1, pUC, pMB1, pBR322. Examples: pGEM, pET, pUC, pQE,
- p15A. Examples: pBad, pACYC
- pSC101.
Copy Number
- ColE1: 300-500 copies
- pUC: 500-700 copies
- pBR322: ~15 copies
- pSC101: ~5 copies
- p15A: 10-12 copies
- R1:
- RK2:
- R6K:
- F1: ~1 copy
Control of Initiation/copy number
- ColE1: Does not require plasmid encoded initiator protein, does require DnaA binding. 1kb. Includes (1) region promoting the synthesis of RNA II, which is the primer for the leading strand (2) sequences that promote stable hybridization of RNA II to DNA (3) sequences that promote RNAse digestion of RNA II, yielding primer for leading strand. RNA I is also transcribed, and sequesters RNA II, so it is unavailable for RNAse H.
- pUC: similar to ColE1
- pBR322: similar to ColE1.
- p15A: similar to ColE1 but different RNAs
- pSC101: iterons
- R1: oriR is bound by RepA promoting initiation. No iterons. Copy number controlled by copA and copB. copA is in RNA that binds the 5’ end of RepA RNA and prevents translation. CopB blocks repA transcription.
- RK2:
- R6K:
- F1: