Glutamine-independent phenotype is adaptable but stable.

<p><b>Top panel:</b> Induction of GLS upon growth in glutamine-containing medium. SUM149-Gln-ind cells growing in Gln-free medium were shifted to Gln-containing medium, and GLS was analyzed by western blotting at different time points after the medium change. <b>Bottom panel:</b> Morphologies of cells growing under different conditions are shown. (A) Gln-ind cells growing without Gln. (B) Gln-ind cells growing in the presence of Gln (they exhibited faster growth and altered morphology upon growth with Gln). (C) Gln-ind cells were maintained in Gln-containing medium for 8 passages and then switched to Gln-free medium for 7 days.</p>