Section 45
Chapter 44,148

Reactivation of an inactive human X chromosome: evidence for X inactivation by DNA methylation

Mohandas, T.; Sparkes, R.S.; Shapiro, L.J.

Science 211(4480): 393-396


ISSN/ISBN: 0036-8075
PMID: 6164095
DOI: 10.1126/science.6164095
Accession: 044147160

Download citation:  

A mouse-human somatic cell hybrid clone, deficient in hypoxanthine-guanine phosphoribosyltransferase (HPRT) and containing a structurally normal inactive human X chromosome, was isolated. The hybrid cells were treated with 5-azacytidine and tested for the reactivation and expression of human X-linked genes. The frequency of HPRT-positives clones after 5-azacytidine treatment was 1000-fold greater than that observed in untreated hybrid cells. Fourteen independent HPRT-positive clones were isolated and analyzed for the expression of human X markers. Isoelectric focusing showed that the HPRT expressed in these clones is human. One of the 14 clones expressed human glucose-6-phosphate dehydrogenase and another expressed human phosphoglycerate kinase. Since 5-azacytidine treatment results in hypomethylation of DNA, DNA methylation may be a mechanism of human X chromosome inactivation.

PDF emailed within 0-6 h: $19.90