A composite DNA element that functions as a maintainer required for epigenetic inheritance of heterochromatin

Epigenetic inheritance of heterochromatin requires sequence - independent propagation mechanisms and input from DNA sequence, but how DNA contributes to inheritance is not understood. Here, we identify a DNA element ( term ed the “maintainer” ) that is necessary and sufficient for epigenetic inheritance of preexisting histone H3 lysine 9 methylation (H3K9me) and heterochromatin i n the fission yeast Schizosaccharomyces pombe . In wild - type cells, d espite its requirement for maintenance of H3K9me, the maintainer cannot establish de novo gene silencing. The maintainer is a composite 1307 - base pair DNA element with binding sites for the Atf1/Pcr1 and Deb1 transcription factors and the O rigin R ecognition C omplex (ORC) and can be converted to a silencer in cells with lower rates of H3K9me turnover , suggesting that it participate s in recruiting the H3K9 methyltransferase Clr4 / Suv39h . T hese results suggest tha t histone H3K9me is only heritable when it can collaborate with maintainer - associated DNA - binding proteins that help recruit the enzyme responsible for its epigenetic deposition . Overall design: Examination of genomic localization of Atf1/Pcr1, Deb1 and ORC in S.pombe