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Fig. 7. Over-expression of lmx1b and its potential binding partners affects the development of tubules. mRNAs of lmx1b and its potential binding partners were injected either alone (panel A) or in combination (panel B), together with lacZ into one V2 blastomere at the 8-cell stage. The morphology of the tubules was assessed at stage 40 by immunohistochemistry using 3G8 (in purple) and 4A6 (in red) monoclonal antibodies (Vize et al., 1995). The injected side was identified by blue β-galactosidase staining and is indicated by an asterisk (a–d). As comparison, the uninjected side of each embryo was photographed (e–h) lmx1b-injected embryos showed no pronephric phenotype (A–a and e). lim1 injection resulted in the formation of an enlarged proximal tubule mass and wider more distal tubules (A–b and f), whereas ldb1 over-expression caused reduction in size of proximal tubules and in some cases affected formation of the more distal tubules (A–c and g). Co-injection of lmx1b with either lim1 or ldb1 partially rescued these phenotypes (B–b and f and B–c and g). Co-expression of lim1 and ldb1 partially rescued both lim1 and ldb1 phenotypes (B–a and e). Injection of E47 resulted in the formation of slightly enlarged proximal tubule mass without affecting the more distal tubules (A–d and h) whereas co-injection of lmx1b and E47 caused the opposite effect with reduction of pronephric proximal tubules (B–d and h). |
