First published online October 14, 2004
Development 131, 2104e (2004)
© The Company of Biologists Limited
Nkx6: specifying neural fate for millions of years
Nkx6 homeodomain proteins are involved in the development of the central
nervous system (CNS) in insects and vertebrates. Now, two papers in this issue
conclude that Nkx6 proteins have retained their ancestral role in neuronal
fate specification over the 800 million years since insects and vertebrates
diverged, despite their genes being regulated differently in the two groups of
animals. On p. 5221,
Cheesman and colleagues report that Nkx6 proteins have similar CNS expression
patterns in Drosophila and zebrafish, and regulate motoneuron
formation in both animals. They identify a zebrafish nkx6.1 gene and
show that ectopic expression of fly or fish Nkx6 generates extra
motoneurons in both species. By contrast, knockdown of Nkx6.1 protein in
zebrafish reduces motoneuron formation and increases ventral interneuron
formation. On p.
5233, Broihier and
co-workers show that Nkx6 is a key factor in the specification of motoneuron
subtype identity in Drosophila. By analysing hb9 Nkx6 double
mutants, the researchers show that Nkx6 collaborates with the homeodomain
protein Hb9 to specify ventrally projecting motoneuron fate and to repress
dorsally projecting motoneuron fate. Nkx6 also promotes axonogenesis in
Nkx6-positive motoneurons, a role that seems to be conserved in
vertebrates.
Related articles in Development:
- Zebrafish and fly Nkx6 proteins have similar CNS expression patterns and regulate motoneuron formation
- Sarah E. Cheesman, Michael J. Layden, Tonia Von Ohlen, Chris Q. Doe, and Judith S. Eisen
Development 2004 131: 5221-5232.
[Abstract]
[Full Text]
- Drosophila homeodomain protein Nkx6 coordinates motoneuron subtype identity and axonogenesis
- Heather T. Broihier, Alexander Kuzin, Yi Zhu, Ward Odenwald, and James B. Skeath
Development 2004 131: 5233-5242.
[Abstract]
[Full Text]
