The murine Xce locus, first identified by Bruce Cattanach,
infiuences the primary choice of the X
chromosome to be inactivated. Methylation of a GC-rich region (DXPas34)
that includes multiple
34 bp repeats and lies some 15 kb 3′ to Xist has been shown
to vary with Xce haplotype. The
degree of methylation on the active X chromosome at this locus represents
one of the few
molecular correlates of Xce action currently available. Data relating
to the specificity and other
characteristics of this association are presented.