Project description:Although transcription factor(TF)s regulate differentiation-related processes, including dedifferentiation and direct conversion, functional interactions between TFs regulating these processes are not well understood. Here we show that TFs preventing dedifferentiation are able to induce direct conversion. Using a neural lineage cell line and a large number of TFs expressed in it, we found a subset of TFs whose overexpression strongly interfered with dedifferentiation triggered by a procedure to induce induced pluripotent stem cells (iPSC), through a maintenance mechanism of the cell-type-specific transcriptional profile. Strikingly, the maintenance activity of the interfering TF set was strong enough to induce the cell line-specific transcriptional profile when overexpressed in a heterologous cell type. In addition, TFs that interfered with dedifferentiation in hepatic lineage cells involved known TFs with induction activity for hepatic lineage cells. Our results suggest that dedifferentiation suppresses a cell-type-specific transcriptional profile, which is primarily maintained by a small subset of TFs capable of inducing direct conversion. We anticipate that this functional correlation might be applicable in various cell types, which may include cancer cells, and might facilitate identification of TFs with induction activity to understand differentiation and tumorigenesis Examination of binding of 3 transcription factors and histone modifications in Neural progenitor like cells.
Project description:Although transcription factor(TF)s regulate differentiation-related processes, including dedifferentiation and direct conversion, functional interactions between TFs regulating these processes are not well understood. Here we show that TFs preventing dedifferentiation are able to induce direct conversion. Using a neural lineage cell line and a large number of TFs expressed in it, we found a subset of TFs whose overexpression strongly interfered with dedifferentiation triggered by a procedure to induce induced pluripotent stem cells (iPSC), through a maintenance mechanism of the cell-type-specific transcriptional profile. Strikingly, the maintenance activity of the interfering TF set was strong enough to induce the cell line-specific transcriptional profile when overexpressed in a heterologous cell type. In addition, TFs that interfered with dedifferentiation in hepatic lineage cells involved known TFs with induction activity for hepatic lineage cells. Our results suggest that dedifferentiation suppresses a cell-type-specific transcriptional profile, which is primarily maintained by a small subset of TFs capable of inducing direct conversion. We anticipate that this functional correlation might be applicable in various cell types, which may include cancer cells, and might facilitate identification of TFs with induction activity to understand differentiation and tumorigenesis
Project description:The importance of unanchored Ub in innate immunity has been shown only for a limited number of unanchored Ub-interactors. We investigated what additional cellular factors interact with unanchored Ub and whether unanchored Ub plays a broader role in innate immunity. To identify unanchored Ub-interacting factors from murine lungs, we used His-tagged recombinant poly-Ub chains as bait. These chains were mixed with lung tissue lysates and protein complexes were isolated with Ni-NTA beads. Sample elutions were subjected to mass spectrometry (LC-MSMS) analysis.
Project description:Cellular binary fate decisions require the progeny to silence genes associated with the alternative fate. The major subsets of alpha:beta T cells have been extensively studied as a model system for fate decisions. While the transcription factor RUNX3 is required for the initiation of Cd4 silencing in CD8 T cell progenitors, it is not required to maintain the silencing of Cd4 and other helper T lineage genes. The other runt domain containing protein, RUNX1, silences Cd4 in an earlier T cell progenitor, but this silencing is reversed whereas the gene silencing after RUNX3 expression is not reverse. Therefore, we hypothesized that RUNX3 and not RUNX1 recruits other factors that maintains the silencing of helper T lineage genes in CD8 T cells. To this end, we performed a proteomics screen of RUNX1 and RUNX3 to determine candidate silencing factors.