Loebel D A, Johnston P G
School of Biological Sciences, Macquarie University, Sydney, N.S.W., Australia.
Chromosoma. 1993 Jan;102(2):81-7. doi: 10.1007/BF00356024.
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.
通过原位缺口平移法检测了袋鼠活性和非活性X染色体的总体核酸酶敏感性和甲基化情况。使用了亚种沙大袋鼠 - 赤大袋鼠（Macropus robustus robustus；Macropus robustus erubescens）杂种的培养成纤维细胞，从而能够区分父源和母源的X染色体。用DNase I或MspI消化时，活性和非活性X染色体之间未发现差异。当用甲基化敏感限制酶HpaII和HhaI消化染色体时，非活性X染色体标记程度更高。这些结果表明活性和非活性X染色体之间在染色质凝聚方面没有总体差异，且活性X染色体的总体甲基化程度更高。非活性X染色体的这种相对低甲基化可能在X染色体失活中起重要作用，但其功能（如果有）仍有待确定。
