SmaI/XmaI digests

Paul Riggs riggs at
Wed Nov 16 11:55:10 EST 1994

In article <9411142223.AA04169 at>,
P_Norton at CALVIN.JCI.TJU.EDU (Dr. Pamela Norton) wrote:

> Bionetters,
>         As the subject line says, we have been having terrible problems
> getting  a SmaI fragment re-subcloned...

Is it possible that there is a toxic gene product being expressed? It
sounds like there is a selection for a frameshift. What vector are you
using? If it is one of the pUC-like copy number vectors, try adding 0.2%
glucose to turn the lac promoter off more tightly (if it is oriented to
transcribe your gene), and/or incubating the transformation plates at 30oC,
which lowers the copy number.
Paul Riggs
New England Biolabs
riggs at

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