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. Author manuscript; available in PMC: 2009 Sep 15.
Published in final edited form as: Cell Stem Cell. 2009 Apr 3;4(4):336–347. doi: 10.1016/j.stem.2009.02.015

Figure 1. Sphere Formation Triggers Stable Changes in TKO Morphology.

Figure 1

(A) TKOs at passage 4 in monolayer culture.

(B) TKOs lack contact inhibition and form mounds after reaching confluence in culture.

(C) Outgrowth of mounds, such as those shown in (B), subsequently leads to detachment from the plate and sphere formation.

(D) TKO spheres are shown 2 weeks after transfer to a nonadherent plate.

(E) Central cavity formation (arrow) becomes evident in TKO spheres after several weeks in suspension culture.

(F) TKO spheres formed in suspension culture reattached when transferred back to tissue culture plates, and all cells in the spheres migrate back onto the plate to reform a monolayer.

(G) Higher-power view of the boxed region in (F).

(H) Monolayers of sphere-derived cells 2 days after spheres were transferred back to a tissue culture plate.

(I) Cells in (H) after 1 week in culture. Note that cells in (H) and (I) have diverse morphologies, and they are smaller than TKO cells prior to sphere formation (A).