Fig. 7. The activation of Erk MAP kinases is greatly reduced when kidney rudiments are grown in the presence of sodium chlorate, an inhibitor of the synthesis of sulphated glycosaminoglycans that is known to inhibit ureteric bud morphogenesis. The top panels show western blots of complete kidney rudiments cultured in the presence of sodium chlorate, or ureteric buds dissected from such kidney rudiments after their incubation, probed with an antibody that recognises only phosphorylated Erk1/2 (Erk-P); chlorate treatment greatly reduces levels of Erk phosphorylation compared with controls (Normal). The right-most lane shows the even more severe reduction in Erk phosphorylation produced by treating kidney rudiments with PD98059. The bottom panels, showing the same samples probed with an antibody that recognises both phosphorylated (Erk-P) and non-phosphorylated Erk, shows that chlorate and PD98059 treatments have little effect on amounts of Erk protein in the tissue.
