Late fetal hematopoietic failure results from ZBTB11 deficiency despite abundant HSC specification

We have used a conditional mouse model to investigate the role of Zbtb11 specifically in hematopoiesis. When Zbtb11 was deleted in the hematopoietic compartment, embryos died at embryonic day E18.5 with hematopoietic failure. Zbtb11 hematopoietic knockout (Zbtb11hKO) hematopoietic stem cells (HSCs) were overabundantly specified at E14.5 through E17.5 compared to controls. Overspecification was accompanied by loss of stemness, inability to differentiate into committed progenitors and mature lineages in fetal liver, failure to seed fetal bone marrow and total hematopoietic failure. Zbtb11hKO HSCs did not proliferate in vitro and were constrained in cell cycle progression, demonstrating a cell-intrinsic role for Zbtb11 in proliferation and cell cycle regulation in mammalian HSCs. scRNAseq analysis identified Zbtb11-deficient HSCs were underrepresented in an erythroid-primed subpopulation and showed downregulation of oxidative phosphorylation (OXPHOS) pathways and dysregulation of genes associated with the hematopoietic niche. We have identified a cell-intrinsic requirement for Zbtb11-mediated gene regulatory networks in sustaining a pool of maturation-capable hematopoietic stem and progenitor cells. We have compared Zbtb11-deleted LSK/SLAM HSCs with controls that are either heterozygous or WT for the same Zbtb11 deletion. A total of 186 single E14.5 fetal liver Zbtb11hKO and control HSCs were assayed on one 384-well plate. Cells were evenly split between WT and Zbtb11hKO (n=93 for each).