These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Tissue-specific imprinting of the G protein Gsalpha is associated with tissue-specific differences in histone methylation.
    Author: Sakamoto A, Liu J, Greene A, Chen M, Weinstein LS.
    Journal: Hum Mol Genet; 2004 Apr 15; 13(8):819-28. PubMed ID: 14976161.
    Abstract:
    The G protein Gsalpha is imprinted in a tissue-specific manner, being primarily expressed from the maternal allele in some tissues, such as renal proximal tubules. The Gsalpha promoter is unmethylated, but is downstream of a differentially methylated region [the exon 1A differentially methylated region (DMR)] that is methylated on the maternal allele. Maternal Gsalpha null mutations or loss of maternal-specific exon 1A methylation leads to pseudohypoparathyroidism types 1A or 1B, respectively. We now have examined the chromatin state of each parental allele within the exon 1A-Gsalpha promoter region by chromatin immunoprecipitation of samples derived from mice with heterozygous deletions within the region using antibodies to covalently modified histones. The exon 1A DMR had allele-specific differences in histone acetylation and methylation, with histone acetylation and H3 lysine 4 (H3K4) methylation of the paternal allele, and H3 lysine 9 (H3K9) methylation of the maternal allele. Both parental alleles had similar levels of histone acetylation and H3K4 methylation within the Gsalpha promoter and first exon, with no H3K9 methylation. In liver, where Gsalpha is biallelically expressed, both parental alleles had similar levels of tri- and dimethylated H3K4 within the Gsalpha first exon. In contrast, in renal proximal tubules there was a greater ratio of tri- to dimethylated H3K4 of Gsalpha exon 1 in the more transcriptionally active maternal as compared with the paternal allele. These results show that allele-specific differences in Gsalpha expression correlate in a tissue-specific manner with allele-specific differences in the extent of H3K4 methylation, and are the first demonstration that chronic transcriptional activation in mammals is correlated with trimethylation of H3K4.
    [Abstract] [Full Text] [Related] [New Search]