Published on SDB CoRe: Feb 22 2012
Stage of Development: Embryo
The notochord is a rod-like structure of dorsal mesoderm found in all chordate embryos. It is crucial for normal patterning of the neural tube via notochord dependent production of hedgehog proteins. In some chordate lineages, the notochord persists throughout life serving as a primitive axial skeleton. In higher vertebrates, the notochord becomes ossified in regions of the vertebrae and contributes to the intervertebral discs as the nucleus pulposus.
This lateral view of a 3-day old zebrafish embryo illustrates that notochord tissue is actually composed of two distinct tissues: the vacuolated cells in purple (marked by the twhh-memRFP transgene) and the sheath epithelium or chondrocytes in green (marked by the 1.75KB col2a1-memGFP transgene). Both tissues are derived from the chordamesoderm.
This image appeared in Developmental Biology (Volume 356, Issue 1) as part of the 2011 Developmental Biology cover competition.
The twhh-memRFP was generated in:
Distel M., Wullimann, M.F., Köster, R.W. Optimized Gal4 genetics for permanent gene expression mapping in zebrafish. Proc Natl Acad Sci, 2009, 106:13365-70.
The 1.75KB col2a1 memGFP was generated in:
Dale, R.M., Topczewski, J. Identification of an evolutionarily conserved regulatory element of the zebrafish col2a1a gene. Dev Biol, 2011, 357:518-31.
Satoh N.,Tagawa, K., Takahashi, H. How was the notochord born? Evolution & Development, 2012, 14:56-75.