Conference Paper
Unravelling continuous eye growth in teleosts by studying blind cavefish
Stemmer, M., Schuhmacher, L.-N., Foulkes, N.S., Bertolucci, C. and Wittbrodt, J.
Record Number:
3218
Year:
2013
Journal:
AIM 2013
Abstract:
The eyes of many vertebrates are already determined in size at birth and won’t change much
afterwards. By contrast, the teleost eye grows life-long, adapting its relative size to the rest of
the body. To achieve this, all necessary cell types have to be produced continuously and in a
highly organized fashion. A special tissue around the lens called CMZ (ciliary marginal zone)
accomplishes this. The CMZ comprises stem cells, which divide, go through a transit
amplifying zone and finally differentiate into the exact number of cells of each type. This is
particularly necessary to maintain the growing retina and RPE functional at all time during
growth. The mechanisms, which conduct this orchestra of constant eye growth in teleosts are
not understood so far. Which genes are involved? Which cells express these? How is the
CMZ organized, structured and how does it contribute to constant growth? To address these
questions, cave and surface fish models will be used for comparisons. In particular Astyanax
mexicanus, which is a powerful model to investigate constant eye growth. During
development of the cavefish the eye initially starts developing, but degenerates eventually in
comparison to its surface dwelling form. Differentiation of later retinal cell types seems to be
missing at a certain developmental stage and apoptosis finally leads to the degenerated eye in
the adult cavefish. Phreatichthys andruzzii, another cave dwelling teleost with a similar
phenotype of degenerated eyes, shows that only the early born retinal ganglion cells develop,
while the other six cell types are not detectable. Hence, layering of the retina does not
proceed. We propose a similar scenario for A. mexicanus. Detailed in situ analyses for P.
andruzzii will be presented and discussed.
Times Cited:
2