6 The Roles of BMPs, BMP Antagonists,
and the BMP Signaling Transducers
Smad1 and Smad5 During Dorsoventral
Patterning of the Zebrafish Embryo
M. Hild, A. Dick, H. Bauer, S. Schulte-Merker, P Haffter,
T. Bouwmeester, and M. Hammerschmidt
6.1
Early Zebrafish Development and Embryonic Patterning ....... 82
6.2
What We Know from Studies in the Frog ................... 83
6.3
The Genetics of the Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 85
6.4
Morphology of Dorsalized and Ventralized Zebrafish Mutants . . . 86
6.5
Analysis of Dorsoventral Phenotypes with the Help
of Molecular Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.6
Expression Patterns of bmp2b, bmp4, bmp7, chordino,
andfollistatin ......................................... 89
6.7
dino, swirl, and snailhouse Are chordino, bmp2b, and bmp7 .... 93
6.8
Chordino Functions via Bmp2b and Bmp7 .................. 95
6.9
Long-Range Effects of Chordino Signaling. . . . . . . . . . . . . . . . .. 96
6.10 Tolloid/Bmpl Acts as an Inhibitor of Chordino . . . . . . . . . . . . . .. 97
6.11
Zebrafish smadl and smad5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 98
6.12
somitabun Is smad5 .................................... 99
6.13
Smad5 Is Involved in the Mediation of Early Bmp2b Signaling.. 101
6.14 The Three Phases of Dorsoventral Pattern Formation . . . . . . . . .. 10 1
References ................................................. , 103