title: Detection of nonrandom X chromosome inactivation.
abstract: This unit describes a PCR-based assay for distinguishing between the two X chromosomes in female cells and assessing the percentage of cells having each parental X chromosome active. Methylation of CpG residues in gene promoters is a major mechanism of transcriptional silencing. In mammalian female cells, hypermethylation is the way in which one X chromosome is inactivated. The X-inactivation assay described in the Basic Protocol relies on methylation sensitivity. In this unit, the highly polymorphic and therefore typically heterozygous (CAG)n region of the 5 end of the coding region of the human androgen receptor gene (HUMARA), at Xq11.2, is used to distinguish and compare the methylation activity of the X chromosomes.
authors.affiliation: Children's Research Institute, Washington, DC, USA.
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Thouin
authors.forename: James M
authors.initials: JM
authors.lastname: Giron
authors.forename: Eric P
authors.initials: EP
authors.lastname: Hoffman
mesh_terms: D000818:Animals; D018899:CpG Islands; D019175:DNA Methylation; D020868:Gene Silencing; D006801:Humans; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011944:Receptors, Androgen / Q000235:genetics; D049951:X Chromosome Inactivation
chemical_list: D011944:Receptors, Androgen