FIG 6.

Egr1 and Egr3 promote cell proliferation during β-selection in ShcFFF mice expressing thymocytes. (A) Sorted DN3E thymocytes (CD4⁻ CD8⁻ CD3⁻ c-kit⁻ CD44⁻ CD25⁺) from control and Lck-Cre/ShcFFF mice retrovirally transduced with Egr1 or Egr3 or control vector expressing GFP were seeded on OP9-DL1 stromal cells, and differentiation to later stages was assessed on day 5. (B) Absolute numbers of total DN thymocytes in the coculture were determined at days 2 and 5 of coculture. (C) Proliferation of retrovirally infected ShcFFF and Lck-Cre/ShcFFF DN3E thymocytes labeled with CellTrace violet and cultured with OP9-DL1 stromal cells and assessed on day 5 by measuring the dilution of the violet dye by cytometry. Data are representative of the results of two experiments performed with 6 animals per genotype.