SupF selection in E. coli - HELP!

[Karen Usdin]

In article <ashok.15.2CD66E60 at biochemistry.cwru.edu>, you wrote:
> I am currently doing experiments integrating a "mini-retrovirus"
> containing a SupF tRNA gene into target DNA in vitro.
> 
> I am interested in efficient SupF selection in transformed 
> E.coli

Invitrogen sells an E. coli strain (MC1061/P3) (both competent and
electrocompetent versions) that has the following genotype

ara F139, F(araABC-leu)7679, galU, galK, FlacX74, (r-k,m+k), strA, deoR+,
rpsL, thi, mcrB, {p3:amber ampR, amber tetR, KmR}

This strain allows selection for supF [by suppression of the amber
mutations in the ampR or tet resistance genes carried on the P3 episome
(Obviously if your vector carries both Amp resistance and Tet resistance
the selection will not work!!)] It also is mcrB making it useful for
propagating methylated DNA.

Karen Usdin
Section on Genomic Structure and Function
NIDDK, National Institutes of Health