Chromatin remodeling by WSTF-ISWI at the replication site: opening a window of opportunity for epigenetic inheritance?

During DNA replication, chromatin states have to be accurately transmitted from the parental to the daughter strands for faithful epigenetic inheritance. Chromatin remodelling factors at the replication site are thought to be involved in this process. Recent work adds ATP-dependent nucleosome remodelling factors to this category of enzymes.

The Williams syndrome transcription factor interacts with PCNA to target chromatin remodelling by ISWI to replication foci.

Chromatin states have to be faithfully duplicated during DNA replication to maintain cell identity. It is unclear whether or how ATP-dependent chromatin-remodelling factors are involved in this process. Here we provide evidence that the Williams syndrome transcription factor (WSTF) is targeted to replication foci through direct interaction with the DNA clamp PCNA, an important coordinator of DNA and chromatin replication.

WSTF-ISWI chromatin remodeling complex targets heterochromatic replication foci.

The Williams Syndrome Transcription Factor (WSTF), the product of the WBSCR9 gene, is invariably deleted in the haploinsufficiency Williams-Beuren Syndrome. Along with the nucleosome-dependent ATPase ISWI, WSTF forms a novel chromatin remodeling complex, WICH (WSTF-ISWI chromatin remodeling complex), which is conserved in vertebrates. The WICH complex was purified to homogeneity from Xenopus egg extract and was found to contain only WSTF and ISWI.