Figure legend. Neural crest cells derived from ES cells |
(1) Epigenetics in germ cells
Many testicular germ cell-specific genes are retroposons, most of which contain a CpG-rich region within their ORFs. We discovered that in somatic cells methylation of CpG dinucleotides within the ORF represses its promoter and that demethylation is necessary for gene expression in spermatogenic cells. We are currently examining the molecular basis of epigenetic modifications, including DNA methylation and histone methylation, that occur within a distinct genomic region in germ cells.
(2) Unique structure of sperm chromatin
The haploid genome in the mammalian sperm nucleus is packaged into a highly compact structure containing protamines and some remaining histones. We are currently analyzing the physiological importance of the somatic-like, histone-containing regions of sperm chromatin.
(3) Establishment of neural crest stem cell lines from ES cells and application of these cell lines in regenerative medicine