C Ratineau1, A Ronco, A B Leiter. 1. Division of Gastroenterology and GRASP Digestive Disease Center, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Abstract
BACKGROUND & AIMS: The early region of simian virus 40 (SV40) encodes 2 transforming proteins, large T (Tag) and small t antigen, that produce neuroendocrine tumors in the intestine and the pancreas when expressed in secretin cells of transgenic mice. METHODS: Two SV40 early-region transgenes containing a deletion that eliminated expression of the small t antigen were expressed in transgenic mice under control of the secretin gene. The 2 lines of mice, one expressing the native large T antigen and the other T antigen with a mutation in its N-terminal J domain, were examined to determine which biological activities of the SV40 early region were required for tumorigenesis. RESULTS: Most animals expressing wild-type large T antigen developed pancreatic insulinomas and lymphomas and died between 3 and 6 months of age. However, small intestinal neoplasms were extremely rare in the absence of small t antigen expression. Transgenic lines expressing the J domain mutant failed to develop tumors. CONCLUSIONS: Transformation of secretin-producing enteroendocrine cells by SV40 requires functional cooperation between intact large T and small t oncoproteins. In contrast, large T antigen alone is sufficient to induce tumors in the endocrine pancreas and thymus.
BACKGROUND & AIMS: The early region of simian virus 40 (SV40) encodes 2 transforming proteins, large T (Tag) and small t antigen, that produce neuroendocrine tumors in the intestine and the pancreas when expressed in secretin cells of transgenic mice. METHODS: Two SV40 early-region transgenes containing a deletion that eliminated expression of the small t antigen were expressed in transgenic mice under control of the secretin gene. The 2 lines of mice, one expressing the native large T antigen and the other T antigen with a mutation in its N-terminal J domain, were examined to determine which biological activities of the SV40 early region were required for tumorigenesis. RESULTS: Most animals expressing wild-type large T antigen developed pancreatic insulinomas and lymphomas and died between 3 and 6 months of age. However, small intestinal neoplasms were extremely rare in the absence of small t antigen expression. Transgenic lines expressing the J domain mutant failed to develop tumors. CONCLUSIONS: Transformation of secretin-producing enteroendocrine cells by SV40 requires functional cooperation between intact large T and small t oncoproteins. In contrast, large T antigen alone is sufficient to induce tumors in the endocrine pancreas and thymus.
Authors: Susan Schonhoff; Laurie Baggio; Christelle Ratineau; Subir K Ray; Jill Lindner; Mark A Magnuson; Daniel J Drucker; Andrew B Leiter Journal: Mol Cell Biol Date: 2005-05 Impact factor: 4.272