|ZFIN ID: ZDB-PUB-110713-54|
Developmental expression of muscarinic receptors in the eyes of zebrafish
Nuckels, R.J., Forstner, M.R., Capalbo-Pitts, E.L., and García, D.M.
|Source:||Brain research 1405: 85-94 (Journal)|
|Registered Authors:||Nuckels, Richard|
|Keywords:||muscarinic acetylcholine receptor, retina, development, zebrafish|
|PubMed:||21741623 Full text @ Brain Res.|
Nuckels, R.J., Forstner, M.R., Capalbo-Pitts, E.L., and García, D.M. (2011) Developmental expression of muscarinic receptors in the eyes of zebrafish. Brain research. 1405:85-94.
ABSTRACTIn previous work, we have shown that light-adaptive pigment granule dispersion can be induced in vitro by treating retinal pigment epithelium (RPE) isolated from bluegill retina with acetylcholine or its analog carbachol and that these agents act through muscarinic receptors to induce pigment granule dispersion. RPE is a monolayer of tissue found between the neural retina and the choroid. In fish, RPE has long apical projections enmeshed with the distal part of photoreceptors, reaching down to the level of their nuclei. The RPE disperses melanin pigment granules into the apical projections to shield light-sensitive photoreceptor outer segments from photobleaching when fish are under bright-light conditions. During development, RPE begin to respond to light at 5 days post-fertilization, raising the question of whether responsiveness is correlated to receptor expression. Here, we isolate, clone and sequence chrm-odd receptor genes in zebrafish, characterize them phylogenetically and observe their expression in the eyes of the zebrafish at different developmental stages using RT-PCR and immunofluorescence microscopy. We find that zebrafish express six unique chrm-odd receptor subtypes: chrm1a, chrm1b, chrm3a, chrm3b, chrm5a and chrm5b — and these receptors are differentially expressed during development. Our phylogenetic analysis confirms the assignments of chrm1b and chrm5b, isolated here, as well as other muscarinic receptor genes and their duplicates and suggests previously described muscarinic receptors may need to be reclassified. Differences between the expression patterns of ostensibly duplicated genes raise the possibility that subtle differences between the duplicates may enable refined regulation of specific developmental events.