Journal
DEVELOPMENT
Volume 134, Issue 5, Pages 845-855Publisher
COMPANY BIOLOGISTS LTD
DOI: 10.1242/dev.02780
Keywords
teleost; telencephalon; subpallium; olfactory bulbs; LIM-homeodomain; Nkx; Dlx; GABA; proliferation; hypothalamus; cavefish; Astyanax mexicanus
Categories
Funding
- NEI NIH HHS [R01 EY014619, EY01-46190] Funding Source: Medline
- NATIONAL EYE INSTITUTE [R01EY014619] Funding Source: NIH RePORTER
Ask authors/readers for more resources
Ventral midline Sonic Hedgehog ( Shh) signalling is crucial for growth and patterning of the embryonic forebrain. Here, we report how enhanced Shh midline signalling affects the evolution of telencephalic and diencephalic neuronal patterning in the blind cavefish Astyanax mexicanus, a teleost fish closely related to zebrafish. A comparison between cave- and surface-dwelling forms of Astyanax shows that cavefish display larger Shh expression in all anterior midline domains throughout development. This does not affect global forebrain regional patterning, but has several important consequences on specific regions and neuronal populations. First, we show expanded Nkx2.1a expression and higher levels of cell proliferation in the cavefish basal diencephalon and hypothalamus. Second, we uncover an Nkx2.1b-Lhx6-GABA-positive migratory pathway from the subpallium to the olfactory bulb, which is increased in size in cavefish. Finally, we observe heterochrony and enlarged Lhx7 expression in the cavefish basal forebrain. These specific increases in olfactory and hypothalamic forebrain components are Shh-dependent and therefore place the telencephalic midline organisers in a crucial position to modulate forebrain evolution through developmental events, and to generate diversity in forebrain neuronal patterning.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available