title: The Barr body is a looped X chromosome formed by telomere association.
abstract: We examined Barr bodies formed by isodicentric human X chromosomes in cultured human cells and in mouse-human hybrids using confocal microscopy and DNA probes for centromere and subtelomere regions. At interphase, the two ends of these chromosomes are only a micron apart, indicating that these inactive X chromosomes are in a nonlinear configuration. Additional studies of normal X chromosomes reveal the same telomere association for the inactive X but not for the active X chromosome. This nonlinear configuration is maintained during mitosis and in a murine environment.
authors.affiliation: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
authors.forename: C L
authors.initials: CL
authors.lastname: Walker
authors.forename: C B
authors.initials: CB
authors.lastname: Cargile
authors.forename: K M
authors.initials: KM
authors.lastname: Floy
authors.forename: M
authors.initials: M
authors.lastname: Delannoy
authors.forename: B R
authors.initials: BR
authors.lastname: Migeon
mesh_terms: D000818:Animals; D002460:Cell Line; D002503:Centromere / Q000648:ultrastructure; D015342:DNA Probes; D006801:Humans; D006822:Hybrid Cells / Q000166:cytology; D007399:Interphase; D051379:Mice; D008938:Mitosis; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D013194:Staining and Labeling; D014960:X Chromosome / Q000502:physiology / Q000648:ultrastructure*
chemical_list: D015342:DNA Probes