ChIP-Chip Designs to Interrogate the Genome of Xenopus Embryos for Transcription Factor Binding and Epigenetic Regulation

Background: Chromatin immunoprecipitation combined with genome tile path microarrays or deep sequencing can be used to study genome-wide epigenetic profiles and the transcription factor binding repertoire. Although well studied in a variety of cell lines, these genome-wide profiles have so far been little explored in vertebrate embryos. Principal Findings: Here we report on two genome tile path ChIP-chip designs for interrogating the Xenopus tropicalis genome. In particular, a whole-genome microarray design was used to identify active promoters by close proximity to histone H3 lysine 4 trimethylation. A second microarray design features these experimentally derived promoter regions in addition to currently annotated 5' ends of genes. These regions truly represent promoters as shown by binding of TBP, a key transcription initiation factor. Conclusions: A whole-genome and a promoter tile path microarray design was developed. Both designs can be used to study epigenetic phenomena and transcription factor binding in developing Xenopus embryos.