The histone acetyltransferase KAT6B modulates proliferation related to differentiation in mouse embryonic stem cells

COSENTINO S; SOLARI C; BARAÑAO L; GUBERMAN A; VAZQUEZ ECHEGARAY C; PETRONE MV; SEVLEVER G; WAISMAN A; FRANCIA M; MIRIUKA S

Puerto Varas, Décima Región de Los Lagos

Congreso; ?Molecular Biosystems? Conference 2017; 2017

The transition between transcriptional programs associated with Stem Cell (SC) differentiation is related tochanges in chromatin structure. KAT6B is a transcriptional coactivator with histone acetyltransferase activity that isimportant for the establishment and self-renewal of adult neural SC, and loss of only one allele leads to intellectualdisability in humans. It was reported that KAT6B gene possess a regulatory element highly occupied by EmbryonicSC (ESC) key transcription factors (TFs), but the relevance of this chromatin modifier in ESC remains to beestablished.The aim of this work was to study the role of KAT6B in ESC. We found that KAT6B is expressed in mouseESC (mESC) and is repressed along differentiation. Moreover, our results also suggest that its expression isregulated by pluripotency TFs Nanog and Oct4. We used the CRISPR/Cas9 strategy to generate KAT6B knockoutmESC lines. We selected a clone with a frameshift mutation that generated a premature stop codon in bothalleles (KAT6B -/-), and confirmed the lack of KAT6B protein expression by Western blot. This clone displayed nosignificant differences to the wild type (WT) control cells regarding the expression of pluripotency markers. However,we observed that the morphology of the cell colonies showed a more flatten phenotype compared to WT.Remarkably, KAT6B -/- mESC had higher proliferation rates than WT when they exit the pluripotent state in differentnon-directed and directed differentiation protocols. We speculate that these changes in proliferation may affect thedifferentiation efficiency of these stem cells.These results suggest that KAT6B is relevant in the differentiation of mESC, and provides a platform to studythe epigenetic mechanisms of normal development as well as human disease. We consider that comprehension ofESC chromatin structure regulation is critical to their future application.