PU.1-c-Jun interaction is crucial for PU.1 function in myeloid development

• Published in: Communications biology Vol. 5; no. 1; p. 961
• Main Authors: Zhao, Xinhui, Bartholdy, Boris, Yamamoto, Yukiya, Evans, Erica K., Alberich-Jordà, Meritxell, Staber, Philipp B., Benoukraf, Touati, Zhang, Pu, Zhang, Junyan, Trinh, Bon Q., Crispino, John D., Hoang, Trang, Bassal, Mahmoud A., Tenen, Daniel G.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.09.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 13/100; 38/61; 631/136/232/2059; 631/337/572/2102; 631/45/612/822; 631/532/1542; 96/31; Activator protein 1; Animals; Binding Sites; Biology; Biomedical and Life Sciences; Bone marrow; c-Jun protein; Cell differentiation; Cell Differentiation - genetics; ETS protein; Fetuses; Hematopoiesis - genetics; Hematopoietic stem cells; Hepatocytes; Lethality; Life Sciences; Lymphocytes B; Macrophages; Mice; Monocytes; Mutants; Mutation; Progenitor cells; Promoter Regions, Genetic; Promoters; Proto-Oncogene Proteins c-jun; PU.1 protein; Transcription Factor AP-1 - genetics; Transcription factors
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-022-03888-7

The Ets transcription factor PU.1 is essential for inducing the differentiation of monocytes, macrophages, and B cells in fetal liver and adult bone marrow. PU.1 controls hematopoietic differentiation through physical interactions with other transcription factors, such as C/EBPα and the AP-1 family member c-Jun. We found that PU.1 recruits c-Jun to promoters without the AP-1 binding sites. To address the functional importance of this interaction, we generated PU.1 point mutants that do not bind c-Jun while maintaining normal DNA binding affinity. These mutants lost the ability to transactivate a target reporter that requires a physical PU.1-c-Jun interaction, and did not induce monocyte/macrophage differentiation of PU.1-deficient cells. Knock-in mice carrying these point mutations displayed an almost complete block in hematopoiesis and perinatal lethality. While the PU.1 mutants were expressed in hematopoietic stem and early progenitor cells, myeloid differentiation was severely blocked, leading to an almost complete loss of mature hematopoietic cells. Differentiation into mature macrophages could be restored by expressing PU.1 mutant fused to c-Jun, demonstrating that a physical PU.1-c-Jun interaction is crucial for the transactivation of PU.1 target genes required for myeloid commitment and normal PU.1 function in vivo during macrophage differentiation. The transcription factor PU.1 recruits c-Jun as a co-activator to promoters without AP-1 binding sites, and mice with point mutations in PU.1 that disrupts the interaction between PU1 and c-Jun have defects in PU.1 dependent blood lineages, including macrophages and B cells.