Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Dosage compensation in mammals is accomplished by the transcriptional silencing of a single X chromosome in female cells, a process termed X inactivation. A cytogenetically defined region of the X chromosome, the X-inactivation center (Xic), is necessary in cis for this process. Although the precise nature of the Xic remains unknown, a key component, the Xist gene, has been shown to be essential for X inactivation. In XX somatic cells, Xist RNA is specifically transcribed from the inactive X chromosome, which is otherwise essentially heterochromatic. Previous studies aimed at defining the proximal limit of the Xic have indicated that it lies within 30 kb upstream of the Xist promoter. Here we describe a novel gene, Enox (expressed neighbor of Xist), that maps to an unmethylated CpG island 10 kb upstream of Xist. Enox transcripts are antisense relative to Xist, highly heterogeneous, and apparently noncoding. In female somatic tissue Enox partially escapes from X inactivation. We discuss the implications of these findings in relation to our understanding of the Xic.


Journal article



Publication Date





236 - 244


Animals, Antigens, Neoplasm, CpG Islands, DNA, Complementary, Dosage Compensation, Genetic, Female, Mice, Polymerase Chain Reaction, RNA, RNA, Long Noncoding, RNA, Untranslated, Transcription Factors, X Chromosome