Two ribeye genes in teleosts: the role of Ribeye in ribbon formation and bipolar cell development.

Wan L, Almers W, Chen W
J Neurosci. 2005 25 (4): 941-9

PMID: 15673675 · PMCID: PMC6725632 · DOI:10.1523/JNEUROSCI.4657-04.2005

Ribeye is the only known protein specific to synaptic ribbon, but its function is unclear. We show that the teleost fish, Fugu and zebrafish, have two ribeye genes, ribeye a and ribeye b. Whole-mount in situ hybridization revealed that ribeye a is expressed in tissues containing synaptic ribbons, including the pineal gland, inner ear, and retina. Ribeye b is absent in the pineal gland. In the retina, ribeye a is expressed in both photoreceptors and bipolar cells, whereas ribeye b is detected only in photoreceptors. To study the function of Ribeye a in retina, we depleted it by morpholino antisense oligos. Fish deficient in Ribeye a lack an optokinetic response and have shorter synaptic ribbons in photoreceptors and fewer synaptic ribbons in bipolar cells. Their bipolar cells still target Syntaxin-3 proteins to the inner plexiform layer and have abundant vsx1 mRNA. However, they lack large synaptic terminals and show increased apoptosis. Rod bipolar cells are fewer in number and/or deficient in PKCalpha. Recovery of Ribeye a levels rescues the optokinetic response, increases the number of PKCalpha-positive bipolar cells, and stops apoptosis. We conclude that Ribeye a is important for late steps in bipolar cell development.

MeSH Terms (12)

Animals Apoptosis Eye Proteins Gene Expression Regulation, Developmental Interneurons Larva Oligodeoxyribonucleotides, Antisense Photic Stimulation Presynaptic Terminals Retina Takifugu Zebrafish

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