Reg1/3 degrade Nfkbiz mRNA and mediate HSPC lineage choice. Reg1/3 normally ensure that Nfkbiz is degraded, thereby preserving balanced lymphomyeloid output. However, in the absence of Reg1/3, HSC/MPP become strongly myeloid skewed. Figure adapted from the article by Uehata et al that begins on page 243.