Controlling elements in the mouseX-chromosome III. Influence upon both parts of anXdivided by rearrangement

Abstract

SUMMARY: Data are presented which support the conclusion that in thefleckedtranslocation,T (1; X) Ct, there is a spread of inactivation into both sides of the autosomal region inserted into theX. This would indicate that both parts of the dividedXare subject to theX-inactivation process. The data also demonstrate that the inactivation of autosomal genes lying near each end of the insertion are modified by theX-chromosome controlling element system,Xce. Since the element modifies the heterozygous expression ofX-linked genes on one side of the insertion, it would therefore be expected that it similarly modifies the heterozygous phenotypes of those on the other side. The data thus support the concept that the controlling element is the master gene, receptor site or inactivation centre which regulates theXinactivation process.