Cullin 4b complex targets IRGM1 to regulate Wnt signaling and intestinal

Hierarchical organization of intestine relies on their stem cells by self-renew and producing committed progenitors. Although signals like Wnt are known to animate the continued renewal by maintaining intestinal stem cells (ISCs) activity, molecular mechanisms especially E3 ubiquitin ligases that modulate ISCs 'stemness' and supportive niche have not been well understood. Here, we investigated the role of Cullin 4B (Cul4b) in regulating ISC functions.We conclude that Cul4b is essential for ISC self-renewal and Paneth cell function by targeting Irgm1 and modulating Wnt signaling. Our results demonstrate that Cul4b is a novel ISC stemness and niche regulator. Overall design: 1. Tissues-Intestinal epithelial-specific deletion of Cul4b (pVillin-Cre; Cul4bfn/Y, KO) and its wildtype control (WT) 2. Organoids- Intestinal epithelial-specific deletion of Cul4b (pVillin-Cre; Cul4bfn/Y, IKO) and its wildtype control (IWT) 3. Organoids-inducible deletion of Cul4b (CAG-CreERT2; Cul4bfn/Y, OKO) and its wildtype control (OWT). Intestinal tissues and were organoids generated by deep sequencing, using illumina hiseq Xten.