journal contribution
posted on 2024-08-15, 07:47 authored by Nancy B.J. Arthur, Keegan A. Christensen, Kathleen Mannino, Marianna B. Ruzinova, Ashutosh Kumar, Agata Gruszczynska, Ryan B. Day, Petra Erdmann-Gilmore, Yiling Mi, Robert Sprung, Conner R. York, Robert R. Townsend, David H. Spencer, Stephen M. Sykes, Francesca Ferraro Supplementary Figure 7. (A) UMAP projection of 36085 cells from MycT58N/+ and Myc+/+ mice colored by genotype, as indicated in the legend. (B) UMAP projection of 36085, split by genotype and colored by the combined expression of Mpo (Myeloperoxidase) and Elane (Elastase, Neutrophil Expressed) transcripts. In yellow are GMP cells, that strongly express both transcripts. (C) UMAP projection of 36085 cells split by genotype and colored by the combined expression of Cd177 and Ngp (neutrophil granule protein). In yellow are granulocytopoietic progenitors, that express high levels of both transcripts. (D) Trajectory analysis of 36085 showing the temporo-spatial expression of Myc (cells that express Myc are in shades of red). (E) Venn diagram showing the percentage overlap in scRNA-seq DEGs between the overexpression and the knockin mouse model. Comparisons are: Empty vector*GMP vs. MycT58N*GMP and MycT58N/+* GMP vs. Myc+/+*GMP for the overexpression and the knockin, respectively. 55% of the DEGs (8334 genes) are shared between the two models. (F) Schematic summary of the nucleocytoplasmic transport components’ transcripts that are upregulated >2 folds in MycT58N/+ versus Myc+/+(created with BioRender.com) (G) Enrichment plots (top) and heatmaps of the leading-edge genes in each pathway (bottom), showing the differential enrichment on Ribosome Biogenesis, Pyrimidine metabolism and Pluripotency pathways in MycT58N/+ GMP-like cells. (H) Enrichment plots (top) and heatmaps of the leading-edge genes in each pathway (bottom), showing the enrichment of Hematopoietic cell lineage and Immune pathways in Myc+/+ GMP-like cells.
Funding
Gabrielle’s Angel Foundation for Cancer Research (GAFCR)
Gilead Research Scholars (GRS)
Center for Cancer Research (CCR)
Alvin J. Siteman Cancer Center (SCC)
History
ARTICLE ABSTRACT
Somatic missense mutations in the phosphodegron domain of the MYC gene (MYC Box I or MBI) are detected in the dominant clones of a subset of patients with acute myeloid leukemia (AML), but the mechanisms by which they contribute to AML are unknown.
To investigate the effects of MBI MYC mutations on hematopoietic cells, we employed a multi-omic approach to systematically compare the cellular and molecular consequences of expressing oncogenic doses of wild type, threonine-58 and proline-59 mutant MYC proteins in hematopoietic cells, and we developed a knockin mouse harboring the germline MBI mutation p.T58N in the Myc gene.
Both wild-type and MBI mutant MYC proteins promote self-renewal programs and expand highly selected subpopulations of progenitor cells in the bone marrow. Compared with their wild-type counterparts, mutant cells display decreased cell death and accelerated leukemogenesis in vivo, changes that are recapitulated in the transcriptomes of human AML-bearing MYC mutations. The mutant phenotypes feature decreased stability and translation of mRNAs encoding proapoptotic and immune-regulatory genes, increased translation of RNA binding proteins and nuclear export machinery, and distinct nucleocytoplasmic RNA profiles. MBI MYC mutant proteins also show a higher propensity to aggregate in perinuclear regions and cytoplasm. Like the overexpression model, heterozygous p.T58N knockin mice displayed similar changes in subcellular MYC localization, progenitor expansion, transcriptional signatures, and develop hematopoietic tumors.
This study uncovers that MBI MYC mutations alter RNA nucleocytoplasmic transport mechanisms to contribute to the development of hematopoietic malignancies.
