GSE15844
Genome-wide mapping of Nuclear Factor I binding sites using ChIP-Seq in WT and NFI-C knock-out MEFs
The Nuclear Factor I (NFI) family of DNA binding proteins (also called CAAT box transcription factors or CTF) is involved both in replication of adenoviral DNA and in regulation of gene expression. Using chromatin immuno-precipitation and high throughput sequencing (method termed ChIP-Seq) we performed genome-wide mapping of Nuclear Factor I DNA binding sites in mouse embryonic fibroblasts. We found that in vivo and in vitro NFI binding specificities are identical, since previously established position weight matrix was found to accurately predict binding sites for NFI group of proteins. Positional correlation between + and - strand ChIP-Seq tags revealed that NFI is a nucleosome-binding protein, unlike some other transcription factors. We further found that NFI binding correlates with the specific histone modification H3K4me3, the marker of transcribed promoters. Combining ChIP-Seq with the microarray expression data, we found that NFI associates with promoters with higher transcription level. We estimate that transcribed promoters may be more accessible to transcription factor binding than their nearby regions since NFI preferentially bind their DNA target sites located around transcription start sites. Knocking-out one of the NFI proteins (NFI-C), reduced the occupancy of predicted sites, however at the same time indicating that cells could compensate the missing protein with the other members of the family. Keywords: ChIP-Seq (chromatin immunoprecipitation and high throughput sequencing) Overall design: ChIP-Seq (chromatin immunoprecipitation and high throughput sequencing) using antibody against NFI family of transcription factors in two cell types (wild type and NFI-C knock-out mouse embryonic fibroblasts MEFs)