Characterization of Ribeye Subunits in Zebrafish Hair Cells Reveals That Exogenous Ribeye B-Domain and CtBP1 Localize to the Basal Ends of Synaptic Ribbons

Sheets, L., Hagen, M.W., Nicolson, T.
PLoS One   9: e107256 (Journal)
Registered Authors
Nicolson, Teresa, Sheets, Lavinia
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Eye Proteins/chemistry
  • Eye Proteins/genetics*
  • Eye Proteins/metabolism
  • Gene Expression Regulation, Developmental
  • Hair Cells, Auditory/metabolism*
  • Hair Cells, Auditory/ultrastructure
  • Larva/genetics
  • Larva/growth & development
  • Larva/metabolism
  • Plasmids/metabolism
  • Protein Structure, Tertiary
  • Protein Subunits/chemistry
  • Protein Subunits/genetics*
  • Protein Subunits/metabolism
  • Repressor Proteins/chemistry
  • Repressor Proteins/genetics*
  • Repressor Proteins/metabolism
  • Synapses/metabolism*
  • Synapses/ultrastructure
  • Synaptic Transmission
  • Transfection
  • Zebrafish/genetics*
  • Zebrafish/growth & development
  • Zebrafish/metabolism
  • Zebrafish Proteins/chemistry
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
25208216 Full text @ PLoS One
Synaptic ribbons are presynaptic structures formed by the self-association of RIBEYE-the main structural component of ribbon synapses. RIBEYE consists of two domains: a unique N-terminal A-domain and a C-terminal B-domain that is identical to the transcription co-repressor C-terminal binding protein 2 (CtBP2). Previous studies in cell lines have shown that RIBEYE A-domain alone is sufficient to form ribbon-like aggregates and that both A- and B- domains form homo-and heterotypic interactions. As these interactions are likely the basis for synaptic-ribbon assembly and structural plasticity, we wanted to examine how zebrafish Ribeye A- and B- domains interact with synaptic ribbons in vivo. To that end, we characterized the localization of exogenously expressed Ribeye A- and B- domains and the closely related protein, CtBP1, in the hair cells of transgenic zebrafish larvae. Unexpectedly, exogenously expressed Ribeye A-domain showed variable patterns of localization in hair cells; one zebrafish paralog of A-domain failed to self-associate or localize to synaptic ribbons, while the other self-assembled but sometimes failed to localize to synaptic ribbons. By contrast, Ribeye B-domain/CtBP2 was robustly localized to synaptic ribbons. Moreover, both exogenously expressed B-domain/CtBP2 and CtBP1 were preferentially localized to the basal end of ribbons adjacent to the postsynaptic density. Overexpression of B-domain/CtBP2 also appeared to affect synaptic-ribbon composition; endogenous levels of ribbon-localized Ribeye were significantly reduced as hair cells matured in B-domain/CtBP2 transgenic larvae compared to wild-type. These results reveal how exogenously expressed Ribeye domains interact with synaptic ribbons, and suggest a potential organization of elements within the ribbon body.
Genes / Markers
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Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes