These data nicely demonstrate the dynamic and reversible changes of histone H3K4 methylation and H3 acetylation in responses to environmental changes in rice.
Glycolysis provides energy for growing lymph vessels, while fatty acid oxidation is a critical metabolic regulator of lymphangiogenesis, in part by promoting nucleotide synthesis as well as by mediating epigenetic changes of histone acetylation, which promotes transcription of key lymphatic genes, and hence venous-to-lymphatic endothelial cell differentiation.
For example, the first genome wide characterization of epi-toxicogenomic changes of histone acetylation profiles at a thirty five nucleotide resolution using Affymetrix Promoter Tiling arrays was reported [39].
These changes of histone acetylation allow chromatin open structure to recruit repressor binding to the hTERT 5'-regulatory region [15], [19].
Furthermore, in mouse embryos, dynamic changes of histone lysine methylation have been described to characterize the first cell cycle, which takes place prior to the zygotic transcription [59].
Beyond the specific example of the HoxA locus, dynamic changes of histone acetylation closely followed the dynamics of transcriptional changes (see Figures S5, S6 and S7 in Supporting Information S1 for example plots of HSPC-TF loci).
Consistent with the role of epigenetic control in a variety of behaviors, the time-scale of epigenetic regulation varies widely, from circadian changes of histone acetylation in the promoter regions of clock genes [4] to long-term memory formation [5].
Combined with the results of this study, we suggest that the differentiation of progenitors into oligodendrocytes requires a series of sequential events and changes of histone marks at distinct loci.
Significant changes of histone acetylation between pair-wise comparisons of different conditions were identified with the Cyber-T-test R-module by using all biological replicates [64] and graphically displayed in kernel density estimation plots.
To identify those regions with statistically significant changes of histone acetylation that parallel our gene expression analysis, we partitioned the ChIP-Seq peak datasets into WT, FDCP and MT-I on the one hand and ME-I, ME-L and MT-L on the other hand, in line with the major partition identified by clustering analysis of gene expression profiles.
