DNA methylation and histone post-translational modification stability in post-mortem brain tissue

Clinical Epigenetics

Table 6 Summary of the immunoreactivity stability of histone acetylation, histone methylation, and DNA cytosine modifications in brain samples*

Epigenetic modification	IHC	IHC—immunoreactivity		IHC—proportion		IHC—counts		Western blot
Epigenetic modification	Human—Cx	Pig—Cx	Mouse—DG	Pig—Cx	Mouse—DG	Neurons	Glia	Pig—Cx
5mC	120	72	72	72	72	72	72	n/a
5hmC	120	72	72	72	72	–	–	n/a
5fC	96	72	72	72	72	–	–	n/a
5caC	96	72	72	72	72	–	–	n/a
H3K4me3	72	72	72	72	72	–	–	72
H3K9me2/K9me3	nd**	72	72	72	72	nd**	nd**	No signal**
H3K27me₃	72	72	72	72	72	72	72	72
H3K36me₃	72	72	72	72	72	–	–	48
H3K9ac	72	48	48	24	24	48	72	Wrong mw
H3K14ac	53	72	72	72	72	72	48	Low signal
H3K27ac	53	24	24	24	24	72	72	Wrong mw
H4K5ac	72	72	48	24	< 24	24	48	< 24
H4K12ac	120	24	24	72	72	72	72	24
H4K16ac	nd	24	24	24	< 24	72	48	No signal
Total H3	nd	24	72	48	48	–	–	72 h
Total H4	nd	72	72	72	48	–	–	72 h
H3panAc	72	nd	nd	nd	nd	nd	nd	24 h

IHC immunohistochemistry, Cx neocortex, DG dentate gyrus of hippocampus, nd not done, n/a not applicable; − not counted; mw molecular weight *Numeric values represent hours post-mortem to formalin fixation (or freezing for Western blots) at which there are no differences compared to samples that were fixed or frozen immediately after death
**H3K9me2,K9me3 antibody was discontinued; H3K9me2 replacement antibody could not be optimized

ISSN: 1868-7083