Figure 5.

Map of the region upstream of the P₁ promoter and positions of primers used. (A) A map of the 7-kb region upstream of Xist. The positions of the previously described pseudogene pS19X (27), the Tsix and Xist genes, and the newly identified pseudogene, pS12X, are shown. The precise 3′ end of Tsix has not been defined (denoted by dotted line). Each asterisk designates a sense and antisense primer pair (see Material and Methods). (B) Strand-specific RT-PCR at positions 1–7 and at Rrm2. Identical results were obtained from male, female, and transgenic ES cells. s, sense (Xist strand); as, antisense (Tsix strand).