ChIP-Rx: Arabidopsis Chromatin Profiling Using Quantitative ChIP-Seq.

Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) is widely used to probe the chromatin landscape of transcription factors, chromatin components, and associated proteins. Conventional ChIP normalization procedures robustly allow estimating differences in local enrichment across genomic regions. Yet, inter-sample comparisons can be biased by technical variability and biological differences.

Hypometabolism to survive the long polar night and subsequent successful return to light in the diatom Fragilariopsis cylindrus.

Diatoms, the main eukaryotic phytoplankton of the polar marine regions, are essential for the maintenance of food chains specific to Arctic and Antarctic ecosystems, and are experiencing major disturbances under current climate change. As such, it is fundamental to understand the physiological mechanisms and associated molecular basis of their endurance during the long polar night. Here, using the polar diatom Fragilariopsis cylindrus, we report an integrative analysis combining transcriptomic, microscopic and biochemical approaches to shed light on the strategies used to survive the polar night.

Histone H1 protects telomeric repeats from H3K27me3 invasion in Arabidopsis.

While the pivotal role of linker histone H1 in shaping nucleosome organization is well established, its functional interplays with chromatin factors along the epigenome are just starting to emerge. Here we show that, in Arabidopsis, as in mammals, H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and H3K27me3 deposition. We further show that, contrasting with its conserved function in PRC2 activation at genes, H1 selectively prevents H3K27me3 accumulation at telomeres and large pericentromeric interstitial telomeric repeat (ITR) domains by restricting DNA accessibility to Telomere Repeat Binding (TRB) proteins, a group of H1-related Myb factors mediating PRC2 cis recruitment.

Arabidopsis Topless-related 1 mitigates physiological damage and growth penalties of induced immunity.

Transcriptional corepressors of the Topless (TPL) family regulate plant hormone and immunity signaling. The lack of a genome-wide profile of their chromatin associations limits understanding of the TPL family roles in transcriptional regulation. Chromatin immunoprecipitation with sequencing (ChIP-Seq) was performed on Arabidopsis thaliana lines expressing GFP-tagged Topless-related 1 (TPR1-GFP) with and without constitutive immunity via Enhanced Disease Susceptibility 1 (EDS1).

Polycomb-dependent differential chromatin compartmentalization determines gene coregulation in .

In animals, distant H3K27me3-marked Polycomb targets can establish physical interactions forming repressive chromatin hubs. In plants, growing evidence suggests that H3K27me3 acts directly or indirectly to regulate chromatin interactions, although how this histone modification modulates 3D chromatin architecture remains elusive. To decipher the impact of the dynamic deposition of H3K27me3 on the nuclear interactome, we combined genetics, transcriptomics, and several 3D epigenomic approaches.