Epigenetics Explorer: Differentiating Cell Types

Published

July 22, 2026

NoteCheck Your Knowledge

  1. Which genes are on either side of HOXA7? Take a screenshot and point to these genes.

  2. What gene or genes are present at chr7:27,110,536-27,132,455? Take a screenshot of this location in the genome.

Note

  • H3K4me3 is a known histone mark on Histone 3 (H3). It occurs on lysine 4 (K4) and has three methyl groups (me3) that indicate active gene expression. In other words, the DNA is open and ready to be accessed.

  • H3K27me3 is a known histone mark on on Histone 3 (H3). It occurs on lysine 27 (K27) and has three methyl groups (me3) that indicate inactive gene expression. In other words, the DNA is closed off and cannot be accessed.

  • The H1-hESC cell line consists of embryonic stem cells.

  • The NHLF cell line consists of lung fibroblasts. Fibroblasts are important for building the connective structures around cells and healing wounds.

NoteCheck Your Knowledge

  1. The two cell lines differ in their gene expression (genes turned on or off). Does this mean that the genome varies as well? Why might gene expression vary?

  2. Locate the HOXA5 gene and record the genome location (e.g., chr7:###-###). Exact numbers will vary a bit, but make sure the whole gene is in frame.

  3. Return to the Broad Histone track menu and select cell line HUVEC (umbilical vein endothelial cells) and K562 (leukemia cells). Do these cell lines have expression turned on or off, or some other pattern for HOXA5?

  4. Return to the Broad Histone track menu and find H3K27ac. Click on the link for this histone mark to learn more about it. Does H3K27ac work more like H3K4me3 or H3K27me3? Take a screenshot showing this histone mark across the HOXA locus (HOXA 1-13).