Tob1 Controls Dorsal Development of Zebrafish Embryos by Antagonizing Maternal β-Catenin Transcriptional Activity

Abstract

Maternal beta-catenin and Nodal signals are essential for the formation of the dorsal organizer, which, in turn, induces neural and other dorsal tissue development in vertebrate embryos. Tob (Transducer of ErbB2) proteins possess antiproliferative properties and are known to influence BMP signaling, but their relationship to other signaling pathways and to embryonic patterning in general was unclear. In this study, we demonstrate that zebrafish tob1a is required for correct dorsoventral patterning. Mechanistically, Tob1a inhibits beta-catenin transcriptional activity by physically associating with beta-catenin and preventing the formation of beta-catenin/LEF1 complexes. Although Tob1a can also inhibit the transcriptional activity of the Nodal effector Smad3, its role in limiting dorsal development is executed primarily by antagonizing the beta-catenin signal. We further demonstrate that Tob family members across species share similar biochemical properties and biological activities.

Nusap1 is essential for neural crest cell migration in zebrafish

“…Whole-mount in situ hybridization followed standard procedure with minor modifications (Thisse et al 2001). Quantitative RT-PCR was performed as previously described (Xiong et al, 2006). Specific pairs of primers were referred to followings: 5'-AGACTGCTGTAAGGAGTGTCCTC-3' (chd forward), 5'-CCATGAAGTCCTCTATGCATTCCG-3' (chd reverse), 5'-CAGAGCTCACTTAGGGAAAGGCTC-3' (bmp2 forward), 5'-CCAATAGTCTAGTGATGGGCTCCTG-3' (bmp2 reverse), 5'-CCGGTCTGCTCAGTCCAGACC-3' (gata1 forward), 5'-GGAAAGGGCTACTGGACCAGAC-3' (gata1 reverse), 5'-GGA-CAGCCTCCTCCCTAAGGC-3' (ctn forward), 5'-CAGTTCTAGCT-GGTTGATGCGG-3' (ctn reverse), 5'-ATGGATGATGAAATTGCCG-CAC-3' (β-actin forward), 5'-ACCATCACCAGAGTCCATCACG-3' (β-actin reverse), 5'-TCAGACGAGAAGACGGAACA-3' (myod forward), 5'-CACGATGCTGGACAGACAAT-3' (myod reverse), 5'-GGGAC-CATTGTGGTCGACAG-3' (shha forward), 5'-GCTTGAGTTTACT-GACATCCC-3' (shha reverse), 5'-CCCGCGCGGAGCCGCC-GCTGC-3' (sox9b forward) and 5'-GCAGGTGCGGGTACTGG-TCCGC-3' (sox9b reverse) (Maves et al, 2007;Warga et al, 2009).…”

The Amotl2 Gene Inhibits Wnt/β-Catenin Signaling and Regulates Embryonic Development in Zebrafish

“…Maternal ␤-catenin is crucial for the formation of the dorsal organizer before the onset of gastrulation (6,7). In contrast, zygotic Wnt/␤-catenin signaling, which is activated in the ventral and lateral blastoderm during gastrulation, acts to prevent the expansion of the dorsal organizer after the onset of gastrulation (8,9).…”

Coordinate involvement of Nodal-dependent inhibition and Wnt-dependent activation in the maintenance of organizer-specific bmp2b in zebrafish

“…Whole-mount in situ hybridization was performed as previously described (Xiong et al, 2006). Stained embryos were cleared in glycerol and photographed using a digital camera (SPOT Insight) under a Nikon SMZ 1500 microscope.…”