Full length Apc2 containing several amino acid replacements in the 20R1 and 20R5 regions (S610A, D613A, N616A, T619A, S660A,S663A, D666A, S752A, T755A, S758A, S761A, S799A, P802A, S805A, S808A, S877A, S880A, S883A, T886A) is expressed under the control of the native promoter and tagged with EGFP.