Propagating Epigenetic States During DNA Replication

Abstract

The propagation of epigenetic states during DNA replication is critical for maintaining gene expression patterns across cell generations. Phenotypically diverse, but genetically identical, cells within a multicellular organism originate from a single cell, the zygote. During development, the cells derived from this zygote will divide and differentiate along multiple developmental pathways until reaching their final cell fates, with each cell-type expressing a different subset of their common genetic information. Differential gene expression in alternate cell-types in both unicellular and multi-cellular organisms is dependent, in part, upon post-translational modifications to DNA and histones. When the DNA itself is replicated, these post-translational modification patterns must also be replicated in order for epigenetic states to be inherited. The replication of epigenetic states involves many proteins acting in a concerted manner. Failure of one protein to act may have devastating effects on the cell and organism including loss of cell identity, inviability or disease. In this review, we will explore how multiple chromatin and gene expression states are transmitted epigenetically from mother cell to daughter cell during DNA replication and the contribution of replication factors to this process, taking examples from S. cerevisiae, Drosophila and mammals.