Constitutive c-Src signaling is sufficient to trans-differentiate pre-B cells to M-like cells. (A) C10 B-cell progenitors were infected with lentiviruses encoding CA c-Src and analyzed for CD11b expression after 6 days of culture. A representative FACS plot gated on transduced cells is shown (n = 3). (B) Only C10 cells transduced with c-Src CA give rise to adherent cells (right). Note: overgrowing nonadherent cells were washed away before image acquisition. Image was taken 8 days after transduction using a Nikon Eclipse Ti with a ×10 Plan Apochromat objective (NA 0.45) and a Hamamatsu Orca Flash 4.0 camera. (C) May Grünwald-Giemsa staining of adherent C10 cells transduced with c-Src CA reveals M-like morphology. Images were acquired with a Leica DMi1 equipped with a ×40 Plan objective (NA 0.5) and a color camera. Representative images are shown (n = 5 experiments). Scale bars represent 25 μm (B) and 20 μm (C). (D) Only cells transduced with c-Src CA phagocytose fluorescently labeled Escherichia coli. A representative FACS plot is shown (n = 3). (E) Cells transduced with c-Src CA upregulate M genes and downregulate B-cell genes (see supplemental Table 3 for absolute values) (n = 3).