FOR EVERY EPI-MOD THERE's an EPI-ENZYME...

FOR WRITING DNA METHYLATION

Enzyme type: DNA methyltransferases

Example: DNMT3b or DNMT3a

Target: unmethylated cytosines, usually CG

FOR ERASING DNA METHYLATION

Enzyme type: methylcytosine dioxygenase

Example: TET1

Target: methylated cytosines, usually CG

FOR WRITING HISTONE LYSINE ACETYLATION

Enzyme type: Histone Acetyl transferase (HAT)

Example: p300

Target: H3K27

FOR REMOVING HISTONE LYSINE ACETYLATION

Enzyme type: Histone Deacetylase (HDAC)

Example: HDAC3

Target: H3K9

FOR ADDING HISTONE METHYL GROUPS

Enzyme type: Histone Methyltransferase

Example: G9a

Target: H3K9

FOR REMOVING HISTONE METHYL GROUPS

Enzyme type: HISTONE DEMETHYLASE

Example: LSD1

Target: H3K4

There are many, many more. Most eukaryotes have multiple types of EPIGENETIC MODIFYING enzymes and multiple isoforms of each enzyme type, each of which is capable of forming unique complexes with a variety of co-regulators. For example humans have more than a dozen different HDACs. Researchers are currently testing which EPI-ENZYMES are most suitable for custom adaptation to EPIGENETIC EDITING and many "dead" Cas9 fusions have been made. Sometimes it's only a portion of the enzyme like the catalytic domain. This means, EPI-ENGINEERING TOOLS built on HOMING ENYZMES are truly customize-able.