Stringent vs. relaxed replication
Plasmid replication control is usually controlled by balancing the levels of a positive and a negative regulator of replication. For some plasmids (pMB1/colE1 replicons) the positive regulator is an RNA and in others (e.g. pSC101) it is a protein. Plasmids with a protein positive regulator will not replicate in the absence of protein production - stringent control (although not the same as the stringent response due to a shortage of loaded tRNAs). Plasmids with an RNA positive regulator will continue to replicate in the absence of protein production. This is termed relaxed control. High yields of plasmid may be obtained by halting protein production (via chloroamphenicol) when the culture reaches a high density and then continuing incubation for a number of hours. This might be of practical relevance when prepping the 1 and 3 series of Synthetic Biology plasmids.--BC 19:05, 3 Sep 2005 (EDT)
- Novick RP, Clowes RC, Cohen SN, Curtiss R 3rd, Datta N, and Falkow S. Uniform nomenclature for bacterial plasmids: a proposal. Bacteriol Rev. 1976 Mar;40(1):168-89.
|pBR322 and its derivatives||pMB1||15-20|
|pACYC and its derivatives||p15A||10-12|
|pSC101 and its derivatives||pSC101||5|
|Incompatibility group||Negative control element||Comment|
|colE1[5, 6], pMB1||RNAI||controls processing of pre-RNAII into primer. pUC is derived from pBR322 (a single mutation in the pBR322 Primer RNA and deletion of the rop gene) which is derived from a pMB1 replicon, and cannot co-reside with the colE1 incompatibility group.|
|IncFII, pT181||RNA||controls synthesis of RepA protein|
|P1, F, R6K, pSC101, p15A||iterons||sequesters RepA protein|
Replication origins in different incompatibility groups are compatible. Replication origins in the same incompatibility group are not.
Note: searching for cloning vector <insert vector name> when looking for vector sequences in NCBI Entrez Nucleotide search. It helps to cut down on the number of hits.
- F plasmid
- pSCANS genbank vector info cookbook
- pSC101 replication origin
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original discovery of ColE1 plasmid
- Error fetching PMID 4610576:
use of ColEI as a vector
- Error fetching PMID 4879515:
Discusses transferable drug resistance in Escherichia coli (i.e. plasmids with resistance markers)
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Discusses generation of plasmids by shearing DNA, their transformation and replication.
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Discusses use of vector to propagate other DNA fragments
- Novagen pET vector table
- table with links to properties/sequences of pET vectors
- note: slow to load
- Plasmids at EcoliWiki.org
- EcoliWiki.org has entered many plasmids that are available for annotation. Included are plasmid maps, features and sequences.