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TADS ENRICHED IN HISTONE H1.2 STRONGLY OVERLAP WITH THE B COMPARTMENT, INACCESSIBLE CHROMATIN AND AT-RICH GIEMSA BANDS

An epigenetic characterization of Giemsa bands (G bands) performed by researchers of the IBMB has revealed their utility as epigenetic units to investigate the differential distribution of linker histones. Giemsa staining of metaphase chromosomes results in a characteristic banding useful for identification of chromosomes and its alterations. Staining of G positive bands decreases with GC content. High GC bands are enriched in active histone marks, RNA polymerase II and SINEs, and associate to gene richness, gene expression and early replication. Histone H1 variants also distribute heterogeneously among G bands: H1X is enriched at high GC bands and H1.2 is abundant at low GC, compacted bands. According to epigenetic features and H1 content, G bands can be organized in clusters useful to compartmentalize the genome. Besides, Hi-C analysis has shown that TADs with high H1.2/H1X ratio strongly overlap with B compartment, late replicating and inaccessible chromatin, and low GC bands. Serna et al. propose that GC content is a strong driver of chromatin compaction and 3D genome organization, that Giemsa staining recapitulates this organization denoted by high-throughput techniques, and that H1 variants distribute at distinct chromatin domains.

 

This research has been performed by the ‘Chromatin regulation of human and viral gene expression’ group (Dr. Albert Jordan) of the IBMB, in collaboration with researchers from CRG-CNAG (Dr. Marc A. Martí-Renom).

Serna-Pujol N, Salinas-Pena M, Mugianesi F, Lopez-Anguita N, Torrent-Llagostera F, Izquierdo-Bouldstridge A, Marti-Renom MA, Jordan A (2020) TADs enriched in histone H1.2 strongly overlap with the B compartment, inaccessible chromatin and AT-rich Giemsa bands. FEBS Journal doi: 10.1111/febs.15549.

GraphicalAbstract_figure copia Albert Jordan
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