B cell stimulation changes the structure and higher-order organization of the inactive X chromosome.

ABSTRACT: X chromosome inactivation (XCI) equalizes X-linked gene expression between sexes. B cells exhibit dynamic XCI, with Xist RNA/heterochromatic marks absent on the inactive X (Xi) in naive B cells but returning following mitogenic stimulation. The impact of dynamic XCI on Xi structure and maintenance was previously unknown. Here, we find dosage compensation of the Xi with state-specific XCI escape genes in naive and in vitro-activated B cells. Allele-specific OligoPaints indicate similar Xi and active X (Xa) territories in B cells that are less compact than in fibroblasts. Allele-specific Hi-C reveals a lack of TAD-like structures on the Xi of naive B cells and stimulation-induced alterations in TAD-like boundary strength independent of gene expression. Notably, Xist deletion in B cells chang

SUBMITTER: Sierra I 

PROVIDER: S-EPMC11998099 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature