For additional validation, we selected histone H3 lysine 27 acetylation because this modification has not been previously shown to be altered in CRC 19Protein immunostaining on western blots confirmed the increased K27 acetylation at H3 (Determine 3 ) and immunohistochemical staining of paired CRC and corresponding normal tissue sections revealed nuclear localisation of acetylated H3 protein (Determine four ).

The exception to the rule is the DOT1 family, members of which methylate K79 within the globular region of histone H3 and that are structurally not related to SET-area proteins 4 - 6 Recent work suggests that SET-domain-containing proteins methylate a few proteins in addition to histones (see later)