Morris, H. M. | bioRxiv Science

bioRxiv2024

Id1 Promotes Clonal Hematopoiesis in Mice with Tet2 Loss of Function

Hematopoietic malignancies emerge through the gradual acquisition of genetic mutations within hematopoietic stem and progenitor cells (HSPCs). Mutations that occur early in disease progression impart a selective growth advantage to HSPCs, which allows them to expand and contribute to a substantial percentage of mature blood cells. This increased expansion is termed clonal hematopoiesis (CH) and is a preleukemic phase associated with an increased risk of developing leukemia. Inhibitor of DNA binding 1 (ID1) protein is a transcriptional regulator of proliferation/differentiation of neuronal, muscle, hematopoietic and other cells, and is frequently overexpressed in cancer. Id1 is expressed at low levels in normal HSCs and is induced by growth factors and other mediators of inflammatory stress and promotes HSPC proliferation in vitro and in vivo. Since chronic inflammation is associated with the progression of hematopoietic malignancies, reducing Id1 expression during CH may be therapeutic. Mutations in TET2 are frequently observed in patients with CH, and Tet2-/-mice develop CH that progress to hematopoietic malignancies. Id1 is upregulated in murine Tet2-/- HSPCs and in AML, CMML and MDS patient samples with TET2 mutations. Genetic ablation of Id1 in Tet2-/- HSPCs reduces HSPC expansion/self-renewal/CH, extramedullary hematopoiesis, myeloid skewing, genetic instability and delays the onset of disease. Mechanistically, p16 expression, senescence and apoptosis were increased and proliferation decreased in Tet2-/-; Id1-/- HSPCs. Thus, ID1 may represent a potential therapeutic target to reduce CH, hematopoietic hyperplasia, and delay the onset of disease. One Sentence SummaryGenetic ablation of Id1 in Tet2-/- mice rescues clonal hematopoiesis by increasing CDKI expression, apoptosis, senescence, and differentiation, and reducing cell growth.

cancer biology↗

bioRxiv2021

Reconfigurable asymmetric protein assemblies through implicit negative design

Asymmetric multi-protein complexes that undergo subunit exchange play central roles in biology, but present a challenge for protein design. The individual components must contain interfaces enabling reversible addition to and dissociation from the complex, but be stable and well behaved in isolation. Here we employ a set of implicit negative design principles to generate beta sheet mediated heterodimers which enable the generation of a wide variety of structurally well defined asymmetric assemblies. Crystal structures of the heterodimers are very close to the design models, and unlike previously designed orthogonal heterodimer sets, the subunits are stable, folded and monomeric in isolation and rapidly assemble upon mixing. Rigid fusion of individual heterodimer halves to repeat proteins yields central assembly hubs that can bind two or three different proteins across different interfaces. We use these connectors to assemble linearly arranged hetero-oligomers with up to 6 unique components, branched hetero-oligomers, closed C4-symmetric two-component rings, and hetero-oligomers assembled on a cyclic homo-oligomeric central hub, and demonstrate such complexes can readily reconfigure through subunit exchange. Our approach provides a general route to designing asymmetric reconfigurable protein systems.

synthetic biology↗