Methylation is reversible.

Methylation is reversible.

Until the end of last year it was unclear whether methylation of histone H3 Lysine 4 (H3-K4) was reversible, unlike the acetylation/deacetylation process, which was known to be dynamic.

H3-K4 methylation is linked to accessibility of regions of DNA and active transcription of target genes. The paper suggests that LSD1 acts as a histone demethylase through an oxidation reaction, and that LSD1 is therefore a transcriptional corepressor. The argument of the break through paper that supports the hypothesis is that inhibition of LSD1 increases H3-K4 methylation and causes derepression of transcription target genes.

The paper is Histone Demethylation Mediated by the Nuclear Amine Oxidase Homolog LSD1, Shi, Y., Lan, F., Matson, C., Mulligan, P., Whetstine, J.R., Cole, P.A., Casero, R.A. and Shi, Y., Cell, Volume 119, Issue 7, Pages 941-953 (29 December 2004). There is an accompanying review article in the same issue of the journal.

Here's a link giving some background to the research that was done and describing the moment Yujiang Shi realised what he had found: http://focus.hms.harvard.edu/2004/Dec17_2004/genetics.html

Ingrid Baade