DNA methylation in the developing marsupial embryo.

摘要: Marsupial development differs from early of placental mammals in that the blastocyst is unilaminar, so both embryonic and extraembryonic cells are derived a single layer (protoderm) which faces cavity. Also, all female marsupial conceptuses far examined show preferential paternal X-inactivation. To test for possible correlation between cell position, X-inactivation DNA hypomethylation, preparations three regions, embryo, vascular yolk sac avascular sac, were digested with methyl-specific restriction endonucleases, separated on agarose gels end-labelled 32P-dCTP. The size distribution fragments obtained indicated levels methylation: high methylation DNA, intermediate hypomethylation DNA. degree repeat sequences, observed as discrete bands HpaII digests, was correlated overall tissue Thus, difference similar to described mouse conceptus, outside position fetal precursor did not correlate hypomethylation. tiny fragments, indicate presence CpG-rich islands evident digests. In these associated gene transcription provide one route cloning unique sequences.