Regulation of DCC localization by HTZ-1/H2A.Z and DPY-30 does not correlate with H3K4 methylation levels

PLoS One. 2011;6(10):e25973. doi: 10.1371/journal.pone.0025973. Epub 2011 Oct 5.

Abstract

Dosage compensation is a specialized form of gene regulation that balances sex-chromosome linked gene expression between the sexes. In C. elegans, dosage compensation is achieved by the activity of the dosage compensation complex (DCC). The DCC binds along both X chromosomes in hermaphrodites to down-regulate gene expression by half, limiting X-linked gene products to levels produced in XO males. Sequence motifs enriched on the X chromosome play an important role in targeting the DCC to the X. However, these motifs are not strictly X-specific and therefore other factors, such as the chromatin environment of the X chromosome, are likely to aid in DCC targeting. Previously, we found that loss of HTZ-1 results in partial disruption of dosage compensation localization to the X chromosomes. We wanted to know whether other chromatin components coordinated with HTZ-1 to regulate DCC localization. One candidate is DPY-30, a protein known to play a role in DCC localization. DPY-30 homologs in yeast, flies, and mammals are highly conserved members of histone H3 lysine 4 (H3K4) methyltransferase Set1/MLL complexes. Therefore, we investigated the hypothesis that the dosage compensation function of DPY-30 involves H3K4 methylation. We found that in dpy-30 animals the DCC fails to stably bind chromatin. Interestingly, of all the C. elegans homologs of Set1/MLL complex subunits, only DPY-30 is required for stable DCC binding to chromatin. Additionally, loss of H3K4 methylation does not enhance DCC mislocalization in htz-1 animals. We conclude that DPY-30 and HTZ-1 have unique functions in DCC localization, both of which are largely independent of H3K4 methylation.

Publication types

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

MeSH terms

  • Animals
  • Caenorhabditis elegans / enzymology
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / metabolism*
  • Chromatin / metabolism
  • Dosage Compensation, Genetic / genetics*
  • Histone Methyltransferases
  • Histone-Lysine N-Methyltransferase / deficiency
  • Histones / chemistry*
  • Histones / genetics
  • Histones / metabolism*
  • Lysine*
  • Male
  • Methylation
  • Nuclear Proteins / metabolism*
  • X Chromosome / genetics
  • X Chromosome / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Chromatin
  • Histones
  • Nuclear Proteins
  • dpy-30 protein, C elegans
  • Histone Methyltransferases
  • Histone-Lysine N-Methyltransferase
  • Lysine