SummaryAs the premier model organism in biomedical research, the laboratory mouse shares the majority of protein-coding genes with humans, yet the two mammals differ in significant ways. To gain greater insights into both shared and species-specific transcriptional and cellular regulatory programs in the mouse, the Mouse ENCODE Consortium has mapped transcription, DNase I hypersensitivity, transcription factor binding, chromatin modifications, and replication domains throughout the mouse genome in diverse cell and tissue types. By comparing with the human genome, we not only confirm substantial conservation in the newly annotated potential functional sequences, but also find a large degree of divergence of other sequences involved in transcriptional regulation, chromatin state and higher order chromatin organization. Our results illuminate the wide range of evolutionary forces acting on genes and their regulatory regions, and provide a general resource for research into mammalian biology and mechanisms of human diseases.
Cell lines were not tested for mycoplasma contamination. Commonly misidentified lines (See ICLAC register) No commonly misidentified cell lines were used.
To complement the human Encyclopedia of DNA Elements (ENCODE) project and to enable a broad range of mouse genomics efforts, the Mouse ENCODE Consortium is applying the same experimental pipelines developed for human ENCODE to annotate the mouse genome.
Summary
To broaden our understanding of the evolution of gene regulation mechanisms, we generated occupancy profiles for 34 orthologous transcription factors (TFs) in human-mouse erythroid progenitor, lymphoblast, and embryonic stem cell lines. By combining the genome-wide TF occupancy repertoires, associated epigenetic signals, and TF co-association patterns, we deduced several evolutionary principles of gene regulatory features operating since the mouse and human lineages diverged. The genomic distribution profiles, primary binding motifs, chromatin states, and DNA methylation preferences are well conserved for TF occupied sequences (TF OSs). However, the extent to which orthologous DNA segments are bound by orthologous TFs varies both among TFs and with genomic location: binding at promoters is more highly conserved than binding at distal elements. Importantly, occupancy conserved TF OSs tend to be pleiotropic; they function in multiple tissues and also co-associate with multiple TFs. Single nucleotide variants (SNVs) at sites with potential regulatory functions are enriched in occupancy conserved TF OSs.
Higher-order chromatin organization such as A/B compartments, TADs, and chromatin loops are temporarily disrupted during mitosis 1,2. Since these structures are thought to influence gene regulation, it is important to understand how they are re-established after mitosis. We examined the dynamics of chromosome reorganization by Hi-C after mitosis in highly purified, synchronous cell populations. We observed rapid establishment, gradual intensification, and expansion of A/B compartments. Contact domains form from the "bottom-up" with smaller subTADs forming initially, followed by convergence into multi-domain TAD structures. CTCF is partially retained on mitotic chromosomes and immediately resumes full binding at ana/telophase. In contrast, cohesin is completely evicted from mitotic chromosomes and regains focal binding with delayed Reprints and permissions information is available at www.nature.com/reprints.Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://
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