Problem on transformation

[Long-Cheng li]

Hi, Everybody:

Recently I got a strange problem trying to clone a promoter sequence
into pGL3 enhancer. After transformation, we could get positive  clone
as tested by PCR of the minipreps. The problem was the positive clone
became negative after maxiprep either tested by PCR or digestion. This
phenomona repeated itself several times. If anybody has any suggestion,
please give me a reply. Thanks.

Long

longli at itsa.ucsf.edu