Immunocytochemical evidence for methylation of the inactive X chromosome in human fetal oogonia.
The state of DNA methylation of the X chromosomes of human interphase oogonia from a 46,XX and a 46,XX/47,XXX fetus at 17 weeks of gestation was tested immunocytochemically with an antibody to 5-methylcytosine (5MeC). Of 1637 oogonial nuclei from the 46,XX fetal ovary, 313 (19.1%) contained Barr bodies, of which 93.6% were positive for 5MeC. Of 1780 oogonia from the 46,XX/47,XXX fetus 327 (18.4%) contained Barr bodies; 175 oogonia had one Barr body and 152 had two. Of the single Barr bodies 145 (82.8%) had positive 5MeC reaction product. Of the 152 oogonia from the XXX line, 97 (63.8%) had positive 5MeC on both Barr bodies, 35 (23%) had one positive and one negative, and 20 (13.1%) had no product on either Barr body. This immunocytochemical evidence supports the hypothesis that the DNA of the inactive X-chromosome of the human 17-week gestation oogonium is methylated.
Jagiello
G M
GM
Department of Obstetrics and Gynecology, College of Physicians and Surgeons of Columbia University, New York, New York 10032.
Tantravahi
U
U
Ducayen
M B
MB
Erlanger
B F
BF
D004247:DNA / Q000378:metabolism*; D004303:Dosage Compensation, Genetic; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007150:Immunohistochemistry; D008745:Methylation; D009867:Oogonia / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism*; D014960:X Chromosome
D004247:DNA