| A definitive test of cell-specific gene expression involves testing a gene in all possible cell types, an experiment that is only practical in transgenic mice. A gene consisting of 4.5 kb of Rat Elastase I 5;Constructs containing either metal regulatory elements (MREs) of the mouse metallothionein gene or a murine leukemia virus LTR fused to the elastase promoter at position ;The elastase 5;These studies imply that there are multiple pathways that regulate acinar cell proliferation. SV40 T antigen seems to promote multistage carcinogenesis, activated H-ras-1 induces immediate transformation and normal H-ras-1 and c-myc have little or no effect on pancreatic acinar cells. In transgenic mice, genes that lead to acinar cell transformation are probably rate-limiting in one of these pathways while oncogenes that do not transform acinar cells either do not participate in growth regulation of this cell-type or are not rate-limiting steps in a regulatory pathway. (Abstract shortened with permission of author.). |
