SV40, large T antigen and transformed cells???

Nigel Kenward mbxnjk at
Wed Jul 12 02:40:32 EST 1995

Hi Alistair,
I'm using pcDNA3 successfully to express a weird protein.
The bottom line is this:
In COS1 or 7 (or and other cell with the Large T you get MASSIVE 
overexpression of your protein (if everything else is OK !). This is due 
to the Large T interacting with the relevant site present on pcDNA3.
In cell types that don't have large T you will get overexpression 
(mainly due to the RSV promoter etc) and you will be able to make stable 
transfectants using antibiotic resistance.

Mind you, before you start it might be worth you looking at Promega's 
new plasmid, "pCI-neo". According to promega it produces 40 - 300 x more 
protein than pcDNA3 in stable transfectants, and even better results 
with transient transfections in COS7 cells (see Promega notes no. 51).

Hope this helps. (I don't work for Promega by-the-way)
Nigel Kenward.

                           TEL:+44 (0)115 9249924 ex. 44789
Dept. of Biochemistry      FAX:+44 (0)115 9422225
Queens Medical Centre      Email:mbxnjk at
Clifton Boulevard          URL: 
U.K.                   "Back off man, I'm a scientist!"  -- Bill Murray.

More information about the Methods mailing list