when we do transformation by two plasmid, bacteria can express two of them or it chose one. i want to know that depend on what
Dear Mohnad,
You can transform bacteria with two plasmids if their have different replication origin. For exemple, Rosetta cells (BL21 with pRARE) can be transfomed with pET28 vector; because pRARE and pET28 don't have the same replication origin.
Hi there,
If it's only for protein expression experiment, the replication origin does not really matter: it has happen to me to cotransform bacteria with pET21 and pET28 plasmid which bear the same origin. Stability for the long-term is more problematic.
when i transform BL21 using pET28 and pETDUET, bacteria express two protein and when i run superdex 75 it can not be separate .and two of them have different molecular weight.
one best example of two plasmid working together for transfection is binary plasmid of agrobacterium, visit takara site PRON101. DNA is a classic exaple secondy why you need to put two plasmid in one bacteria,?
This is a comprehensive description of the plasmid ori you might find it helpful (It is our most popular blog ever).
http://blog.addgene.org/plasmid-101-origin-of-replication
i am doing co transformation in BL21 cells i see low plasmid yield when i extract the plasmid and run on gel.
but some time when i increase concentration on antibiotic in my LB i see some bands although not to much prominent but still enough to show them. i feel transformation in BL21 mother strain (not BL21 DE) is a little challenge. i am not sure about how much is compatibility of BL21 mother strain for relaxed or stringent plasmids but i think there is some thing about it that i am not aware of.. kindly open my views about it .. suggestions welcomed
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