Xenopus Bicaudal-C is required for the differentiation of the amphibian pronephros

Abstract

The RNA-binding molecule Bicaudal-C regulates embryonic development in Drosophila and Xenopus. Interestingly, mouse mutants of Bicaudal-C do not show early patterning defects, but instead develop polycystic kidney disease (PKD). To further investigate the molecular mechanism of Bicaudal-C in kidney development, we analyzed its function in the developing amphibian pronephros. Bicaudal-C mRNA was present in the epithelial structures of the Xenopus pronephros, the tubules and the duct, but not the glomus. Inhibition of the translation of endogenous Bicaudal-C with antisense morpholino oligomers (xBic-C-MO) led to a PKD-like phenotype in Xenopus. Embryos lacking Bicaudal-C developed generalized edemas and dilated pronephric tubules and ducts. This phenotype was caused by impaired differentiation of the pronephros. Molecular markers specifically expressed in the late distal tubule were absent in xBic-C-MO-injected embryos. Furthermore, Bicaudal-C was not required for primary cilia formation, an important organelle affected in PKD. These data support the idea that Bicaudal-C functions downstream or parallel of a cilia-regulated signaling pathway. This pathway is required for terminal differentiation of the late distal tubule of the Xenopus pronephros and regulates renal epithelial cell differentiation, which--when disrupted--results in PKD.

MicroRNAs are critical regulators of tuberous sclerosis complex and mTORC1 activity in the size control of the Xenopus kidney

“…The procedure for the in situ hybridizations and the analysis by paraplast sectioning has been previously described (47,48). To generate antisense probes, plasmids were linearized and transcribed as follows: pSK-β1-Na/K-ATPase-EcoRI/T7 (48), pCS2-Igf1-EcoRI/T7 (49), pCS2-Igf2-EcoRI/T7 (49), pCS2-Igf3-EcoRI/T7 (49), pCS2-Igf-Receptor-EcoRI/T7 (49), pCS2-Insulin-EcoRI/T7 (49), pCMV-SPORT6-Insulin-Receptor-SalI/T7 (clone ID: 7011987), pCMV-SPORT6-Insulin-related-Receptor-SmaI/T7 (clone ID: 6639745), pCMV-SPORT6-Irs1-EcoRV/T7 (clone ID: 4407025), pSK-mTOR -EcoRI/T7, pSK-Ncc-EcoRI/T7 (48), pSK-Nkcc2-SmaI/T7 (48), pSK-Raptor-BamHI/T7 (clone ID: XL072d22), pSK-Rictor-EcoRI/T7 (clone ID: XL021i17), pCMV-SPORT6-Sglt1-K-SalI/T7 (50), pSK-Tsc1-EcoRI/T7 (clone ID: XL062p12), and pSK-Tsc2-XhoI/T3 (clone ID: XL091f02).…”

Heat Shock 70-kDa Protein 5 (Hspa5) Is Essential for Pronephros Formation by Mediating Retinoic Acid Signaling

“…3, A-C). Whole mount in situ hybridization and immunostaining experiments were performed to examine the formation of the pronephros in embryos targeted on one side with 30 ng of Hspa5MO2/embryo using marker genes that include pax2 (44), lhx1 (21,22), and ␤1 subunit of Na/K-ATPase (atp1b1) (45). The marker genes pax2 (60%; 18 of 30), lhx1 (67%; 24 of 36), and atp1b1 (85%; 29 of 34) were strongly suppressed on the injected side but not on the uninjected side (Fig.…”

Bicaudal C, a novel regulator of Dvl signaling abutting RNA-processing bodies, controls cilia orientation and leftward flow

“…3A,B), consistent with a conserved role for xBicC in regulating flow. To deplete xBicC in the GRP and floor plate, the morpholino oligonucleotides xBicC MO1 and MO2 (Tran et al, 2007) were injected into the marginal zone of four-cell embryos (Blum et al, 2009). If xBicC MO1/2 was injected on both sides (Fig.…”