Demethylation of somatic and testis-specific histone H2A and H2B genes in F9 embryonal carcinoma cells.
AUTOR(ES)
Choi, Y C
RESUMO
In contrast to many other genes containing a CpG island, the testis-specific H2B (TH2B) histone gene exhibits tissue-specific methylation patterns in correlation with gene activity. Characterization of the methylation patterns within a 20-kb segment containing the TH2A and TH2B genes in comparison with that in a somatic histone cluster revealed that: (i) the germ cell-specific unmethylated domain of the TH2A and TH2B genes is defined as a small region surrounding the CpG islands of the TH2A and TH2B genes and (ii) somatic histone genes are unmethylated in both liver and germ cells, like other genes containing CpG islands, whereas flanking sequences are methylated. Transfection of in vitro-methylated TH2B, somatic H2B, and mouse metallothionein I constructs into F9 embryonal carcinoma cells revealed that the CpG islands of the TH2A and TH2B genes were demethylated like those of the somatic H2A and H2B genes and the metallothionein I gene. The demethylation of those CpG islands became significantly inefficient at a high number of integrated copies and a high density of methylated CpG dinucleotides. In contrast, three sites in the somatic histone cluster, of which two sites are located in the long terminal repeat of an endogenous retrovirus-like sequence, were efficiently demethylated even at a high copy number and a high density of methylated CpG dinucleotides. These results suggest two possible mechanisms for demethylation in F9 cells and methylation of CpG islands of the TH2A and TH2B genes at the postblastula stage during embryogenesis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=360272Documentos Relacionados
- S-phase-specific transcription regulatory elements are present in a replication-independent testis-specific H2B histone gene.
- Characterization of the S-phase-specific transcription regulatory elements in a DNA replication-independent testis-specific H2B (TH2B) histone gene.
- Differential regulation of viral and cellular genes in F9 mouse embryonal carcinoma cells.
- Retroviral vector gene expression in F9 embryonal carcinoma cells.
- Control of beta-interferon expression in murine embryonal carcinoma F9 cells.