Inheritable traits are not only encoded in the sequence of DNA,but also determined by factors 'on top' of the DNA, the epigenetic information ('epi' is classical Greek for 'on top'). Epigenetic phenomena play an important role in the maintenance of gene expression patterns through cell generations, for example in tissue-specific gene expression. A striking example of epigenetic regulation is found in X-chromosome inactivation in mammalian cells, where one of the two X chromosomes is maintained in an inactive, highly condensed state throughout development. In many organisms epigenetic regulation is mediated by DNA methylation, but epigenetic phenomena are also found in organisms where DNA methylation does not take place. The eukaryotic genome is packaged and organized by a plethora of proteins forming the superstructure chromatin that is a major facet of epigenetics. It is very important, therefore, for chromatin structures to be faithfully duplicated during DNA replication to maintain epigenetic information. There is accumulating

P. Varga-Weisz

Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 0TL, UK, e-mail: [email protected]

Progress in Molecular and Subcellular Biology P. Jeanteur (Ed.) Epigenetics and Chromatin © Springer-Verlag Berlin Heidelberg 2005

evidence that chromatin remodeling factors play a key role in facilitating and regulating DNA replication through chromatin and the propagation of epige-netic information during DNA replication. This chapter summarizes our current knowledge about chromatin remodeling factors that have been linked directly to the DNA and chromatin replication process.

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