Related Experiment Video
Updated: Feb 8, 2026

Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
Immature CD8 Single-Positive Thymocytes Are a Molecularly Distinct Subpopulation, Selectively Dependent on BRD4 for
Anne Gegonne1, Qing-Rong Chen2, Anup Dey3
1Experimental Immunology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
None:
T cell differentiation in the thymus proceeds in an ordered sequence of developmental events characterized by variable expression of CD4 and CD8 coreceptors. Here, we report that immature single-positive (ISP) thymocytes are molecularly distinct from all other T cell populations in the thymus in their expression of a gene profile that is dependent on the transcription factor BRD4. Conditional deletion of BRD4 at various stages of thymic differentiation reveals that BRD4 selectively regulates the further differentiation of ISPs by targeting cell cycle and metabolic pathways, but it does not affect the extensive proliferation that results in the generation of ISPs. These studies lead to the conclusion that the ISP subpopulation is not a hybrid transitional state but a molecularly distinct subpopulation that is selectively dependent on BRD4.
More Related Videos
Related Concept Videos
Frequency-dependent Selection
Position-effect Variegation
Chromatin Position Affects Gene Expression
Topologically Associated Domains (TADs)
The 3-dimensional positioning of chromatin in the nucleus influences the...
Molecular Compounds: Formulas and Nomenclature
The Integrated Rate Law: The Dependence of Concentration on Time
Antibiotic Selection

