Search bioRxiv⌕ Search

Biology subjects

Alonso-Gil, D.

Publications and source records attributed to Alonso-Gil, D..

2 recordsLinked to original sources

Context-dependent epigenome rewiring during neuronal differentiation

Transcription factors (TFs) are pivotal in orchestrating lineage decisions and their binding is often accompanied by chromatin remodeling. However, a comprehensive understanding of how cellular and epigenetic contexts influence TF binding and the subsequent activation of lineage-specific programs remains lacking. Here, we dissected the molecular mechanisms underlying the binding of one such TF - Neurog2 and its functional consequences in two cell-types: mouse embryonic stem cells and neural progenitor cells. Our findings reveal that cell-type-specific chromatin accessibility and motif syntax are key determinants for TF binding. While Neurog2 binding primarily leads to chromatin opening, DNA demethylation and increased chromatin interactions, we also uncovered strong indirect, cell-type-specific effects, which ultimately result in vastly different epigenetic landscape. Furthermore, we identify shared and cell-type-specific Neurog2 interactors, including the SWI/SNF and NuRD complexes. Our study shed light on how cellular environment can modulate TF function to establish lineage identity during development.

genomics↗

Different NIPBL requirements of cohesin-STAG1 and cohesin-STAG2

Cohesin organizes the genome through the formation of chromatin loops. NIPBL activates cohesins ATPase and is essential for loop extrusion, but its requirement for cohesin loading is currently unclear. Here we have examined the effect of reducing NIPBL levels on the behavior of the two cohesin variants carrying STAG1 or STAG2 by combining a flow cytometry assay to measure chromatin-bound cohesin with analyses of its genome-wide distribution and genome contacts. We show that NIPBL depletion results in increased cohesin-STAG1 on chromatin that further accumulates at CTCF positions while cohesin-STAG2 diminishes genome-wide. Our data support a model in which NIPBL is not required for initial association of cohesin with chromatin but it is for loop extrusion, which in turn facilitates stabilization of cohesin-STAG2 at CTCF positions after being loaded elsewhere. In contrast, cohesin-STAG1 is loaded and stabilized at CTCF sites even under low NIPBL levels, but genome folding is severely impaired.

cell biology↗