X chromosome-wide analyses of genomic DNA methylation states and gene expression in male and female neutrophils

Proc Natl Acad Sci U S A. 2010 Feb 23;107(8):3704-9. doi: 10.1073/pnas.0914812107. Epub 2010 Feb 2.

Abstract

The DNA methylation status of human X chromosomes from male and female neutrophils was identified by high-throughput sequencing of HpaII and MspI digested fragments. In the intergenic and intragenic regions on the X chromosome, the sites outside CpG islands were heavily hypermethylated to the same degree in both genders. Nearly half of X chromosome promoters were either hypomethylated or hypermethylated in both females and males. Nearly one third of X chromosome promoters were a mixture of hypomethylated and heterogeneously methylated sites in females and were hypomethylated in males. Thus, a large fraction of genes that are silenced on the inactive X chromosome are hypomethylated in their promoter regions. These genes frequently belong to the evolutionarily younger strata of the X chromosome. The promoters that were hypomethylated at more than two sites contained most of the genes that escaped silencing on the inactive X chromosome. The overall levels of expression of X-linked genes were indistinguishable in females and males, regardless of the methylation state of the inactive X chromosome. Thus, in addition to DNA methylation, other factors are involved in the fine tuning of gene dosage compensation in neutrophils.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosomes, Human, X / genetics*
  • DNA Methylation*
  • Female
  • Gene Expression Regulation*
  • Gene Expression*
  • Genes, X-Linked*
  • Humans
  • Male
  • Neutrophils / metabolism
  • Promoter Regions, Genetic
  • Sex Factors