In vitro recombination
of the Cre/loxP system at 37°C.
(A) Quantitation of the recombination products.
M (lane 1), 1 kb DNA ladder marker (Gibco BRL); P and S, product
and substrate, respectively; i, recombination intermediate; *,
unexpected bands (may be due to the site preference of NcoI).
The same quantitation standards (lanes 2–9) as used in
the FLP/FRT system were applied. EcoRI-linearized
pCALNLZ and each denoted amount of the Cre lysate was incubated
for 30 min at 37°C. The recovered DNA
was then digested with NcoI and the densities of
the 4.4 kb products (P4.4) were quantified based on those of the
quantitation standards. One representative result out of three is
shown. (B) Recombination process of the Cre/loxP system. N, NcoI site.