Journal Article
Brain of the blind: transcriptomics of the golden-line cavefish brain
Meng, F., Zhao, Y.H., Titus, T., Zhang, C.G. and Postlethwait, J.H.
Record Number:
3608
Year:
2018
Journal:
Current Zoology
Pages:
765-773
Volume:
64
Abstract:
The genus Sinocyclocheilus (golden-line barbel) includes 25 species of cave-dwelling blind fish
(cavefish) and more than 30 surface-dwelling species with normal vision. Cave environments are
dark and generally nutrient-poor with few predators. Cavefish of several genera evolved convergent
morphological adaptations in visual, pigmentation, brain, olfactory, and digestive systems.
We compared brain morphology and gene expression patterns in a cavefish Sinocyclocheilus
anophthalmus with those of a closely related surface-dwelling species S. angustiporus. Results
showed that cavefish have a longer olfactory tract and a much smaller optic tectum than surface
fish. Transcriptomics by RNA-seq revealed that many genes upregulated in cavefish are related to
lysosomes and the degradation and metabolism of proteins, amino acids, and lipids. Genes downregulated
in cavefish tended to involve “activation of gene expression in cholesterol biosynthesis”
and cholesterol degradation in the brain. Genes encoding Srebfs (sterol regulatory elementbinding
transcription factors) and Srebf targets, including enzymes in cholesterol synthesis, were
downregulated in cavefish brains compared with surface fish brains. The gene encoding Cyp46a1,
which eliminates cholesterol from the brain, was also downregulated in cavefish brains, while the
total level of cholesterol in the brain remained unchanged. Cavefish brains misexpressed several
genes encoding proteins in the hypothalamus–pituitary axis, including Trh, Sst, Crh, Pomc, and
Mc4r. These results suggest that the rate of lipid biosynthesis and breakdown may both be
depressed in golden-line cavefish brains but that the lysosome recycling rate may be increased in
cavefish; properties that might be related to differences in nutrient availability in caves.
Times Cited:
1
Relevent Species:
Related Records:
Chen, Y. R., Chu, X. L., Luo, Z. and Wu, J. (1988)
A new blind cyprinid fish from Yunnan, China with a reference to the evolution of its characters
Chen, Y.R. and Yang, J.X. (1993)Species and origin of cave dwelling Sinocyclocheilus fishes
Chen, Y.R. and Yang, J.X. (1993)A synopsis of cavefishes from China
Yang, J. X. and Chen, Y. R. (1993)The cavefishes from Jiuxiang Limestone Cave of Yunnan, China with reference to character evolutions
Wang, D. and Chen, Y.Y. (1998)On the diagnosis of Sinocyclocheilus and the taxonomic position of its closely related genus Anchicyclocheilus (Cypriniformes: Cyprinidae: Barbinae)
Yue, P. and Chen, Y. (1998)China Red Data Book of Endangered Animals. Pisces
Xiao, H, Zhang, R, Feng, J, Ou, Y., M, Li, W, Chen, S and Zan, R (2002)Nuclear DNA content and ploidy of seventeen species of fishes in Sinocyclocheilus
Zhao, Y.H. and Zhang, C.G. (2009)Threatened fishes of the world: Sinocyclocheilus anophthalmus (Chen and Chu, 1988) (Cyprinidae)
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