Primary tubular epithelial cells (TECs) isolated from the kidneys of a PKD transgenic rat expressing a truncated PC-2 ( PKD2 (1–703)) display higher proliferative activity compared with TECs isolated from normal Sprague-Dawley rats. (A). Whole cell lysates containing equal amounts of protein from TECs isolated from normal Sprague-Dawley rat (SD) and TECs isolated from PKD transgenic rat (Mut) were analyzed by Western blotting for expression of p21, phosphorylated STAT-1, PCNA, tubulin, PC-2, cadherin, vimentin and megalin. All blots are representative of experiments performed on at least two different transgenic animals. Endogenous PC-2 can be seen on long exposures that also bring out high background (not shown) (B). Cell cycle profile of normal (SD) or mutants (Mut) TECs. The results are presented as mean of triplicate counts (three independent cultures) for each animal. ± SEM (ANOVA p < 0.01. * = significant difference). The data are representative of two experiments performed using two different pairs of animals.