Hck inhibits p73α-induced apoptosis. (A). SAOS-2 cells transfected with p73α and Hck, mSH3-Hck or KD-Hck in the ratio of 1:3 were immunostained for p73 and Hck and the percentage of apoptotic cells was scored among expressing and non-expressing cells using morphological criteria. Data represent mean ± S.D. of at least three independent experiments performed on duplicate coverslips. (B) Panels show the morphological features of p73 and Hck expressing cells. Arrowhead shows apoptotic cells and arrows indicate healthy cells. (C) SAOS-2 cells transfected with p73α and Hck or mSH3-Hck in the ratio of 1:3 were immunostained for p73 and cleaved caspase-3 expression. (D) Total RNA isolated from SAOS-2 cells transfected with HA-p73α (200 ng) with or without Hck (1300 ng), mSH3 Hck (1300 ng) and KD Hck (1300 ng) were subjected to RT-PCR analysis as described in Fig. 7E. (E) p73α transactivation function is independent of Tyr-28 phosphorylation. RT-PCR analysis was carried out using RNA isolated from SAOS-2 cells after transfection with indicated expression constructs. Expression levels of gene products were determined using appropriate primers. (UT indicates untransfected).