FIG. 1.

(A) Scheme for the generation of the truncated Tsix (2 lox) and the control 1 lox alleles (see the text for details). The Tsix intron/exon structure, the two putative promoters, and regions deleted in previous studies (10, 19, 39) are indicated. (B) Southern analysis of targeted male and female cell lines after Cre-mediated recombination. DNA was digested with EcoRI and probed with the 5′ internal probe (indicated in panel A) in order to detect the wild-type (1.7-kb), 1 lox (1.1-kb), and 2 lox (1.8-kb) alleles.