Caudal Type Homeobox Transcription Factor 4 (CDX4)

Horn and Ashworth (1995) identified a gene which, like XIST, maps to Xq13.2 within the specific region of the X chromosome, called the X-inactivation center (XIC), thought to play a key role in regulating X inactivation. CDX4 is a member of the 'caudal-related' family of homeobox genes. It is located in the mouse 100 kb distal to Xist and the 2 genes are transcribed convergently.

From an analysis of a panel of YACs derived from the XIC region and flanking Xist, Horn and Ashworth (1995) demonstrated that CDX4 is located proximal to XIST in the human, indicating that both CDX4 and XIST are within the region inverted since mammalian divergence. Unlike Xist, Cdx4 appears to be normally X-inactivated in mice.