Genome-wide analysis of differential transcription in KRAB-ZFP cluster knock-out ES cells and mouse tissues

Mammalian genomes encode several hundred Krüppel-associated box zinc finger proteins (KRAB-ZFPs) that bind DNA in a sequence-specific manner through tandem arrays of C2H2-type zinc fingers and repress transcription via KRAB-dependent recruitment of the silencing cofactor KAP1. The KRAB-ZFP family rapidly amplified and diversified in mammals by segmental gene duplications, mutations, and zinc finger rearrangements likely in response to continued transposable element invasions, but the biological functions and in vivo requirement of these proteins has gone largely unexplored. We determined the genomic binding sites of 61 murine KRAB-ZFPs and genetically deleted five large KRAB-ZFP gene clusters encoding more than 100 of the approximately 360 mouse KRAB-ZFPs. We demonstrate that most KRAB-ZFPs bind to specific retrotransposon families and that many of these retrotransposons are transcriptionally activated in KRAB-ZFP cluster KO ESCs, licensing retrotransposon-derived enhancers to activate nearby genes. RNA-seq analysis of KRAB-ZFP cluster KO ES cells and tissues.