ABSTRACT
ChIP-seq is rapidly becoming a routine technique for the determination of the genome wide association of DNA binding proteins and histone modifications. Here we provide a protocol for the isolation, purification, and immunoprecipitation of DNA fragments associated with a target transcription factor of interest. Although the method makes use of adult mouse hearts, it can, with relative ease, be adapted for the in vivo ChIP isolation of DNA from other cell and tissue sources with the intention of massive parallel sequencing.
Subject(s)
Chromatin Immunoprecipitation/methods , DNA/isolation & purification , High-Throughput Nucleotide Sequencing , Animals , Chromatin , Chromatin Immunoprecipitation/standards , DNA/genetics , Endopeptidase K/chemistry , Humans , Mice , Myocardium/chemistry , Sonication , Tissue FixationABSTRACT
Tbx3, a T-box transcription factor, regulates key steps in development of the heart and other organ systems. Here, we identify Sox4 as an interacting partner of Tbx3. Pull-down and nuclear retention assays verify this interaction and in situ hybridization reveals Tbx3 and Sox4 to co-localize extensively in the embryo including the atrioventricular and outflow tract cushion mesenchyme and a small area of interventricular myocardium. Tbx3, SOX4, and SOX2 ChIP data, identify a region in intron 1 of Gja1 bound by all tree proteins and subsequent ChIP experiments verify that this sequence is bound, in vivo, in the developing heart. In a luciferase reporter assay, this element displays a synergistic antagonistic response to co-transfection of Tbx3 and Sox4 and in vivo, in zebrafish, drives expression of a reporter in the heart, confirming its function as a cardiac enhancer. Mechanistically, we postulate that Sox4 is a mediator of Tbx3 transcriptional activity.
