Murine-specific expression of the transcription factor Csda is induced by a murine-specific transposome carrying POU5F1 binding site. (A) CSDA is expressed during mouse PED, but not in human and bovine PED. CSDA is analyzed by two mouse probe sets (red), four human probe sets (green), and one bovine probe set (blue). (B) ChIP-seq data in mouse ES cells. The region of the mouse genome upstream of the Csda gene contains a functional POU5F1 binding site, which would appear to be competent to bind the POU5F1 protein. Two CTCF-associated TFBSs attract the CTCF insulator and define the boundaries of a genomic regulatory region (yellow) between them. The functional POU5F1 TFBS is carried by a murine-specific transposon Lx8, which is conserved in the mouse and the rat, but not in other mammals. (C) Expression and genome sequence data jointly suggest that the murine lineage gained a regulatory relationship between Pou5f1 and Csda.
