Methylation status of CpG-rich islands on active and inactive mouse X chromosomes.
Single copy probes derived from CpG-rich island clones from Eag I and Not I linking libraries and nine rare-cutter restriction endonucleases were used to investigate the methylation status of CpG-rich islands on the inactive and active X chromosomes (Chr) of the mouse. Thirteen of the 14 probes used detected CpG-rich islands in genomic DNA. The majority of island CpGs detected by rare-cutter restriction endonucleases were methylated on the inactive X Chr and unmethylated on the active X Chr, but some heterogeneity within the cell population used to make genomic DNA was detected. The CpG-rich islands detected by two putative pseudoautosomal probes remained unmethylated on both the active and inactive X Chrs. Otherwise, distance from the X Chr inactivation center did not affect the methylation profile of CpG-rich islands. We conclude that methylation of CpG-rich islands is a general feature of X Chr inactivation.
Norris
D P
DP
Section of Comparative Biology, MRC Clinical Research Centre, Harrow, Middlesex, UK.
Brockdorff
N
N
Rastan
S
S
D000818:Animals; D001483:Base Sequence; D015252:Deoxyribonucleases, Type II Site-Specific; D004303:Dosage Compensation, Genetic; D005260:Female; D006570:Heterochromatin / Q000737:chemistry; D008297:Male; D008745:Methylation; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D014960:X Chromosome / Q000737:chemistry*
D006570:Heterochromatin; D015252:Deoxyribonucleases, Type II Site-Specific