Figure 5.
Pten is a functionally relevant miR-19 target in B-cell lymphomas. (A) Schematic representation of the Pten 3′UTR with the location of the predicted binding sites for members of the miR-17∼92 cluster and sequence alignments between miR-19b and its two predicted binding sites. (B) Pten Western blot on lysates of B-lymphoma cells transduced with the indicated PIG constructs. (Lanes 8,9) For comparison, lysates from miR-17∼92Δ/Δ cell expressing the two Pten shRNAs that scored positive in the in vitro screen were also assayed. (C) Pten immunohistochemistry on lymphoma sections obtained from mice injected with miR-17∼92fl/fl and miR-17∼92Δ/Δ B-lymphoma cells transduced with the indicated miR-17∼92 derivatives (objective, 20×). Brown staining indicates Pten signal. (D) Knockdown of Pten suppresses apoptosis in miR-17∼92Δ/Δ cells. Apoptosis was measured by detecting caspase activity in miR-17∼92fl/fl and miR-17∼92Δ/Δ cells transduced with the indicated retroviruses. (E) Kaplan-Meier survival curve of mice injected with miR-17∼92Δ/Δ lymphoma cells transduced with retroviruses expressing shRNAs against Pten. N = 10 (five mice for shPTEN-1 and five mice for shPTEN-2). For comparison, the survival curves of mice injected with miR-17∼92fl/fl, miR-17∼92Δ/Δ, and miR-17∼92Δ/Δ + miR-19a,b from Figure 2C are included.