large plasmid transformation and deo

Robert Whittier rfwhittier at
Mon Sep 3 04:37:37 EST 2001

Fellow netters,

Occasionally, even in the realm of science, discussions degenerate to
"so-and-so says" type of arguments, and it can be difficult to find out
what the data was.

There is some lab lore that claims that deo- or deoR mutations improve
transformation efficiency of large plasmids into E. coli. I have tried
to search PubMed for the data behind this, but without success. At least
one old post in the archives of this newsgroup attributes the claim to
Douglas Hanahan. Indeed a PNAS paper on which he was senior author
(1990, Vol. 87, pp 4645-4649) starts out the Materials and Methods
section with the statement:

"DH5 was derived from DH1 through the introduction of the deoR mutation,
as will be described elsewhere (D.H., unpublished results)."

I have not been able to find such a paper, and so I'm not sure whether
it was ever published. Given his track record, I'm inclined to give
the good professor a great deal of credence, but I'd still like to
know the data. Does anybody know the relevant publication? If this
deo story has a solid basis, is it true only for Ca+ based methods,
or does it apply to electroporation as well? Any info is welcome,
with a pointer towards the data coming in at the top of my wish list.


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