title: Selective differential staining of sister chromatids of the facultative heterochromatic X chromosome in the female mouse.
abstract: Selective differential staining of sister chromatids for the facultative heterochromatic X chromosome in the female mouse has been achieved by the combination of two differential staining techniques; one for the heterochromatic X chromosome and the other for sister chromatids. Thermal hypotonic treatment moderately destroyed the chromosome structure except for the heterochromatic X in BrdU labelled metaphase cells, resulting in the selective sister chromatid differentiation of this X with Giemsa stain. This technique enables us to know the exact frequency of th spontaneous sister chromatid exchanges in the heterochromatic X without using 3H-TdR labelling for detecting the late DNA replication. The results indicate that the sister chromatid exchange frequency of the heterochromatic X chromosome is not affected by its late DNA replication during S phase, or by the genetic inactivation and the resulting heterochromatinization.
mesh_terms: D000818:Animals; D001399:Azure Stains; D001973:Bromodeoxyuridine; D002842:Chromatids / Q000648:ultrastructure*; D002871:Chromosome Banding; D004303:Dosage Compensation, Genetic; D005260:Female; D006570:Heterochromatin / Q000648:ultrastructure; D006358:Hot Temperature; D051379:Mice; D008807:Mice, Inbred BALB C / Q000235:genetics; D012730:Sex Chromosomes / Q000648:ultrastructure*; D014960:X Chromosome / Q000648:ultrastructure*
chemical_list: D001399:Azure Stains; D006570:Heterochromatin; D001973:Bromodeoxyuridine