Analysis of DNase 1 sensitivity and methylation of active and inactive X chromosomes of kangaroos (Macropus robustus) by in situ nick translation.
The overall nuclease sensitivity and methylation of active and inactive X chromosomes of kangaroos were examined by in situ nick translation. Cultured fibroblasts of subspecies wallaroo-euro (Macropus robustus robustus; Macropus robustus erubescens) hybrids were used, enabling the paternally and maternally derived X chromosomes to be distinguished. No difference was found between the active and inactive X chromosomes with DNase I or MspI digestion. When chromosomes were digested with the methylation sensitive restriction enzymes HpaII and HhaI, the inactive X chromosome was labelled to a greater extent. These results indicate no overall difference in chromatin condensation between the active and inactive X chromosomes and greater overall methylation of the active X chromosome. This relative undermethylation of the inactive X chromosome may be important in X chromosome inactivation, but its function, if any, remains to be determined.
School of Biological Sciences, Macquarie University, Sydney, N.S.W., Australia.
D A
DA
Loebel
P G
PG
Johnston
D000818:Animals; D002478:Cells, Cultured; D002871:Chromosome Banding; D004262:DNA Restriction Enzymes / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism*; D004303:Dosage Compensation, Genetic; D005260:Female; D005821:Genetic Techniques / Q000662:veterinary*; D007614:Macropodidae / Q000235:genetics*; D008677:Metaphase; D008745:Methylation; D014960:X Chromosome / Q000378:metabolism*
D004262:DNA Restriction Enzymes; D003850:Deoxyribonuclease I