Figure 8.

Oncogenic transforming activity of Hydra β‐Catenin. (A) Structures of the applied RCAS constructs (HA, hemagglutinin tag). (B) Agar colony formation of CEF transfected with the empty retroviral RCAS vector, or with RCAS constructs depicted under A. Each 1 × 10⁴ cells were seeded in soft nutrient agar onto MP12 dishes and colonies were scored after 3 weeks. Untransformed control CEF infected with the empty RCAS vector produced very small background colonies, which has been also observed previously 37, 38. Colonies were counted from triplicate dishes. A representative experiment from two independent assays (n = 2) is shown. Vertical bars show standard deviations (SD). Statistical significance was assessed by using a paired Student t‐test (*P < 0.05, **P < 0.01). (C) Immunoblot analysis of ectopically expressed proteins using the indicated antibodies. The antibody directed against the mouse β‐Catenin portion present in the ΔLEF1ΔCTNNB fusion protein also detects the endogenous chicken (ck) Ctnnb (p90).