title: Difference in chromatin packaging between active and inactive X chromosomes by fractionation and allele-specific detection.
abstract: Using a novel method consisting of chromatin fractionation and allele-specific detection, chromatin packaging is compared between active X (Xa) and inactive X (Xi) chromosomes for five tumor cell clones that were derived from inter-subspecific F1 female mice. Separation of heterochromatic (H) and euchromatic (E) fractions is monitored by hybridization with subtelomeric satellite DNA and ribosomal RNA gene and by PCR amplification of p53 gene/pseudogene with one primer set. The H fraction was enriched with satellite and p53 pseudogene probably existing in heterochromatic regions while the E fraction showed inverse, suggesting fair separation. Analysis with seven marker and three gene loci revealed concentration of alleles on Xi in the H fraction and those on Xa in the E fraction, though the concentration levels varied. This implies that the packaging level of Xi is higher than that of active or inactive euchromatin on Xa. Intriguingly, one cell line showed biallelic expression and chromatin relaxation of the Pgk-1 locus, suggesting that the relaxation occur regionally on X chromosome.
authors.affiliation: First Department of Biochemistry, Niigata University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Kuwabara
authors.forename: K
authors.initials: K
authors.lastname: Tsunashima
authors.forename: Y
authors.initials: Y
authors.lastname: Mishima
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: N
authors.initials: N
authors.lastname: Takagi
authors.forename: R
authors.initials: R
authors.lastname: Kominami
mesh_terms: D000483:Alleles; D000818:Animals; D005591:Chemical Fractionation; D002843:Chromatin / Q000378:metabolism*; D003433:Crosses, Genetic; D004303:Dosage Compensation, Genetic; D022041:Euchromatin; D005260:Female; D005354:Fibrosarcoma; D005819:Genetic Markers; D006570:Heterochromatin / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D010735:Phosphoglycerate Kinase / Q000235:genetics; D011110:Polymorphism, Genetic; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014960:X Chromosome / Q000378:metabolism*
chemical_list: D002843:Chromatin; D022041:Euchromatin; D005819:Genetic Markers; D006570:Heterochromatin; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D014157:Transcription Factors; C077885:XIST non-coding RNA; D010735:Phosphoglycerate Kinase