UTX_CHIP_FIBROBLASTS

The recent discovery of a large number of histone demethylases suggests a central role for these enzymes in regulating histone methylation dynamics. Histone H3K27 trimethylation (H3K27me3) has been linked to Polycomb Group (PcG) protein-mediated suppression of Hox genes and animal body patterning, X-inactivation and possibly maintenance of embryonic stem (ES) cell identity. An imbalance of H3K27 methylation due to over-expression of the methylase EZH2 has been implicated in metastatic prostate and aggressive breast cancers. Here we show that the related JmjC domain-containing UTX and JMJD3 catalyze demethylation of H3K27me3. UTX is enriched around the transcription start sites of many Hox genes in primary human fibroblasts where Hox genes are differentially expressed, but is selectively excluded from the Hox locus in ES cells in which Hox genes are largely silent. Consistently, RNAi inhibition of UTX led to increased H3K27me3 levels at some Hox gene promoters. Importantly, Morpholino inhibition of a zebrafish UTX homolog resulted in mis-regulation of Hox genes and a striking posterior developmental defect, which was partially rescued by wildtype, but not catalytically inactive human UTX. Taken together, these findings identified a small family of H3K27 demethylases with important, evolutionarily conserved roles in H3K27 methylation regulation and in animal anterior-posterior development. Keywords: organism_part_comparison_design An organism part comparison experiment design type compares tissues, regions, organs within or between organisms. Controls: UTX occupancy was mapped by chromatin immunoprecipitation using anti-UTX antibody. As control, we performed mock chromatin immunoprecipitation with isotype-matched antibody (IgG). Two color, competitive hybridization experiments were performed to compare genomic DNA enrichment in UTX vs. IgG pulldowns. Experimental variable: We compared primary human fibroblasts from two different anatomic locations--foot and lung.