TY - JOUR
T1 - Temporal separation in the specification of primary and secondary motoneurons in zebrafish
AU - Beattie, Christine E.
AU - Hatta, Kohei
AU - Halpern, Marnie E.
AU - Liu, Hongbo
AU - Eisen, Judith S.
AU - Kimmel, Charles B.
N1 - Funding Information:
We thank the University of Oregon Zebra®sh Facility for technical support and Drs. A. Chandrasekhar and J. Y. Kuwada for sharing unpublished data. This work was supported by an American Cancer Society Postdoctoral Fellowship PF-3982 (C.E.B.), an MRC Centennial Fellowship (M.E.H.), and NIH Grants NS23915 and HD22486.
PY - 1997/7/15
Y1 - 1997/7/15
N2 - In zebrafish there are two populations of motoneurons, primary and secondary, that are temporally separate in their development. To determine if midline cells play a role in the specification of these neurons, we analyzed both secondary and primary motoneurons in mutants lacking floor plate, notochord, or both floor plate and notochord. Our data show that the specification of secondary motoneurons, those most similar to motoneurons in birds and mammals, depends on the presence of either a differentiated floor plate or notochord. In the absence of both of these structures, secondary motoneurons fail to form. In contrast, primary motoneurons, early developing motoneurons found in fish and amphibians, can develop in the absence of both floor plate and notochord. A spatial correspondence is found between secondary motoneurons and sonic hedgehog-expressing floor plate and notochord. In contrast, primary motoneuronal specification depends on the presence of sonic hedgehog in gastrula axial mesoderm, the tissue that will give rise to the notochord. These results suggest that both primary and secondary motoneurons are specified by signals from midline tissues, but at very different stages of embryonic development.
AB - In zebrafish there are two populations of motoneurons, primary and secondary, that are temporally separate in their development. To determine if midline cells play a role in the specification of these neurons, we analyzed both secondary and primary motoneurons in mutants lacking floor plate, notochord, or both floor plate and notochord. Our data show that the specification of secondary motoneurons, those most similar to motoneurons in birds and mammals, depends on the presence of either a differentiated floor plate or notochord. In the absence of both of these structures, secondary motoneurons fail to form. In contrast, primary motoneurons, early developing motoneurons found in fish and amphibians, can develop in the absence of both floor plate and notochord. A spatial correspondence is found between secondary motoneurons and sonic hedgehog-expressing floor plate and notochord. In contrast, primary motoneuronal specification depends on the presence of sonic hedgehog in gastrula axial mesoderm, the tissue that will give rise to the notochord. These results suggest that both primary and secondary motoneurons are specified by signals from midline tissues, but at very different stages of embryonic development.
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U2 - 10.1006/dbio.1997.8604
DO - 10.1006/dbio.1997.8604
M3 - Article
C2 - 9242415
AN - SCOPUS:0030871925
SN - 0012-1606
VL - 187
SP - 171
EP - 182
JO - Developmental biology
JF - Developmental biology
IS - 2
ER -