Figure 1.

Analysis of β-catenin expression, APC status, and Tcf4 expression in the cell lines used. (a) Variable expression of β-catenin. Whole cell lysates were separated on a 6% polyacrylamide gel, blotted, and developed with anti-β-catenin mAb 7D11 or, for control of the amount of protein per lane, with anti-β-actin mAb 5441. (b) Cell line CD-NCM425 and LS 174T have APC with the expected molecular mass, whereas, in CSC-1 and SW480, the APC is truncated. Immunoblots from whole cell lysates were developed with FE9 mAb directed against the NH₂-terminal region of APC. The upper part of the membrane was exposed 10-fold longer than the lower part. Cell lines SW480 and LS 174T were blotted in parallel as controls for truncated and intact APC, respectively. (c) Tcf4 is expresed strongly in all cell lines except CSC-1; 25 μg of total RNA per lane was hybridized with probes for Tcf4 or for β-actin for control of amounts of RNA.