Cultured
Using protein visualization techniques, cell lines stably expressing GFP-fused full-length and mutant APCs were obtained from cultured Xenopus laevis renal epithelial A6 cells. The use of these cells showed that mutant APCs, whose C-terminal region is absent, induced piling up of cells. Furthermore, piled up cells from mutant APC-expressing cell lines were proven to maintain the intercellular adhesive structure, representing a phenomenon similar to polyp formation in individual organisms (mice).
1. An isolated polynucleotide that encodes a mutant adenomatous polyposis coli (APC) protein which induces piling up of cells, wherein the protein consists of a sequence having 95% or higher identity to amino acids 1-859 of SEQ ID NO:1.
2. A vector that comprises the polynucleotide of claim 1 .
3. An isolated cell that comprises an artificially expressed mutant APC protein encoded by the polynucleotide of claim 1 .
4. The cell of claim 3 , which is a mammalian cell.
5. The cell of claim 3 , which is a Xenopus laevis cell.
6. The cell of claim 3 , which is an established cell line.
7. The polynucleotide of claim 1 , wherein the mutant APC protein is a Xenopus laevis protein.
8. The isolated polynucleotide of claim 1 , wherein the polynucleotide encodes a mutant APC protein consisting of the sequence of amino acids 1-859 of SEQ ID NO: 1.