Neoplasms originating from thymic T-cell progenitors and post-thymic mature T-cell subsets account for a minority of lymphoproliferative neoplasms. These T-cell derived neoplasms, while molecularly and genetically heterogeneous, exploit transcription factors and signaling pathways that are critically important in normal T-cell biology, including those implicated in antigen-, costimulatory-, and cytokine-receptor signaling. The transcription factor GATA-3 regulates the growth and proliferation of both immature and mature T cells and has recently been implicated in T-cell neoplasms, including the most common mature T-cell lymphoma observed in much of the Western world. Here we show that GATA-3 is a proto-oncogene across the spectrum of T-cell neoplasms, including those derived from T-cell progenitors and their mature progeny, and further define the transcriptional programs that are GATA-3 dependent, which include therapeutically targetable gene products. The discovery that p300-dependent acetylation regulates GATA-3 mediated transcription by attenuating DNA binding has novel therapeutic implications. As most patients afflicted with GATA-3 driven T-cell neoplasms will succumb to their disease within a few years of diagnosis, these findings suggest opportunities to improve outcomes for these patients.

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We present a versatile single-molecule localization microscopy technique utilizing time-lapse imaging of singleantibody labeling. By performing single-molecule imaging in the subminute time scale and tuning the antibody concentration to create sparse single-molecule binding, we captured antibody labeling of subcellular targets to generate superresolution images. Single-antibody labeling enabled dual-target superresolution imaging using dye-conjugated monoclonal and polyclonal antibodies. We further demonstrate a dual-color strategy to increase the sample labeling density. Single-antibody labeling paves a new way to evaluate antibody binding for superresolution imaging in the native cellular environment.

Single-molecule imaging has provided new insights on weak transient biomolecular interactions with micromolar to millimolar affinity. However, the limited duration of observation has hindered the study of strong and reversible interactions with sub-nanomolar affinity. We report single-molecule interaction microscopy (SMIM), which combines point accumulation for imaging in nanoscale topography (PAINT) with extended imaging durations that enables the study of antibody binding kinetics in the cellular environment. SMIM revealed heterogeneous binding kinetics and the effect of concentration and antibody valency on the association and dissociation rates on antibody-antigen interactions in their cellular environments. We thereby demonstrate SMIM as a versatile single-molecule technique for studying strong, transient biomolecular interactions.