Notch1 signaling ramps up to very high levels in order to drive CD4-CD8- double-negative (DN) thymocytes to the CD4+CD8+ double-positive (DP) stage. During this important phase of T-cell development, which is known as the DN-DP transition, it is unclear whether the Notch1 complex simply strengthens its signal output as an isolated unit or recruits cofactors to amplify its signals. We previously showed that the PIAS-like coactivator Zmiz1 is a direct and context-dependent cofactor of Notch1 in T-cell leukemia. Using conditional knockout mouse models, we show that like inactivation of Notch, inactivation of Zmiz1 impaired the DN-DP transition under steady state and stress conditions. To determine mechanism, we performed RNA-Seq on sorted DN3 cells that were deprived of Zmiz1 signals either acutely (DeltaTamCre) or chronically (DeltaMxCre). To differentiate Notch1-independent from Notch1-dependent target genes, we also performed RNA-Seq on DN3 cells that were deprived of Notch1 signals using the anti-NRR Notch1 antibody. Our data suggests that Zmiz1 selectively amplifies a subset of Notch1 target genes in DN3 cells, such as Myc. SOURCE: Richard,C,McEachin (mceachin@umich.edu) -  University of Michigan

Pluto Bioinformatics

GSE106683: The Zmiz1-Notch1 interaction induces Myc expression to drive steady state and stress thymopoiesis [DN3]