Expression of Cre in EIIa-cre transgenic mice by RT-PCR. Lanes 1-6, cDNA amplified with control primer pairSacII/293. Lanes 7-12, cDNA amplified with primer pair cre1/cre2. Lanes 2, 4, 6, 8, 10, 12 amplified in the presence of RT. Lanes 1, 3, 5, 7, 9, 11 controls amplified without RT. Lanes 1, 2, 7, 8 RNA isolated from leg muscle. Lanes 3, 4, 9, 10 RNA isolated from ovaries. Lanes 5, 6, 11, 12 RNA isolated from bone marrow. Lane 13 molecular marker. Note that primer pair cre1/cre2 amplifies a band of 520 bp and control primer pair SacII/293 amplifies a band of 268 bp.