title: Subversion of T lineage commitment by PU.1 in a clonal cell line system.
abstract: Specification of mammalian T lymphocytes involves prolonged developmental plasticity even after lineage-specific gene expression begins. Expression of transcription factor PU.1 may maintain some myeloid-like developmental alternatives until commitment. Commitment could reflect PU.1 shutoff, resistance to PU.1 effects, and/or imposition of a suicide penalty for diversion. Here, we describe subclones from the SCID.adh murine thymic lymphoma, adh.2C2 and adh.6D4, that represent a new tool for probing these mechanisms. PU.1 can induce many adh.2C2 cells to undergo diversion to a myeloid-like phenotype, in an all-or-none fashion with multiple, coordinate gene expression changes; adh.6D4 cells resist diversion, and most die. Diversion depends on the PU.1 Ets domain but not on known interactions in the PEST or Q-rich domains, although the Q-rich domain enhances diversion frequency. Protein kinase C/MAP kinase stimulation can make adh.6D4 cells permissive for diversion without protecting from suicide. These results show distinct roles for regulated cell death and another stimulation-sensitive function that establishes a threshold for diversion competence. PU.1 also diverts normal T-cell precursors from wild type or Bcl2-transgenic mice to a myeloid-like phenotype, upon transduction in short-term culture. The adh.2C2 and adh.6D4 clones thus provide an accessible system for defining mechanisms controlling developmental plasticity in early T-cell development.
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, 91125 USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Dionne
authors.forename: Kevin Y
authors.initials: KY
authors.lastname: Tse
authors.forename: Angela H
authors.initials: AH
authors.lastname: Weiss
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Franco
authors.forename: David L
authors.initials: DL
authors.lastname: Wiest
authors.forename: Michele K
authors.initials: MK
authors.lastname: Anderson
authors.forename: Ellen V
authors.initials: EV
authors.lastname: Rothenberg
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D019070:Cell Lineage; D049109:Cell Proliferation; D003001:Cloning, Molecular; D005434:Flow Cytometry; D018507:Gene Expression Regulation, Developmental; D006412:Hematopoietic Stem Cells; D020935:MAP Kinase Signaling System; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D022423:Myeloid Cells / Q000378:metabolism; D010641:Phenotype; D011493:Protein Kinase C / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism / Q000502:physiology*; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism / Q000502:physiology*; D019076:Transgenes; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D011493:Protein Kinase C; D011518:Proto-Oncogene Proteins; D015375:Receptors, Interleukin-2; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1