Functional characterization of connexin43 mutations found in patients with oculodentodigital dysplasia.

Junko Shibayama, William Paznekas, Akiko Seki, Steven Taffet, Ethylin Wang Jabs, Mario Delmar, Hassan Musa

Research output: Contribution to journalArticle

Abstract

Specific mutations in GJA1, the gene encoding the gap junction protein connexin43 (Cx43), cause an autosomal dominant disorder called oculodentodigital dysplasia (ODDD). Here, we characterize the effects of 8 of these mutations on Cx43 function. Immunochemical studies have shown that most of the mutant proteins formed gap junction plaques at the sites of cell-cell apposition. However, 2 of the mutations (a codon duplication in the first extracellular loop, F52dup, and a missense mutation in the second extracellular loop, R202H, produced full-length connexins that failed to properly form gap junction plaques. Cx43 proteins containing ODDD mutations found in the N-terminus (Y17S), first transmembrane domain (G21R, A40V), second transmembrane domain (L90V), and cytoplasmic loop (I130T, K134E) do form gap junction plaques but show compromised channel function. L90V, I130T, and K134E demonstrated a significant decrease in junctional conductance relative to Cx43WT. Mutations Y17S, G21R, and A40V demonstrated a complete lack of functional electrical coupling even in the presence of significant plaque formation between paired cells. Heterologous channels formed by coexpression of Cx43WT and mutation R202H resulted in electrically functional gap junctions that were not permeable to Lucifer yellow. Therefore, the mutations found in ODDD not only cause phenotypic variability, but also result in various functional consequences. Overall, our data show an extensive range of molecular phenotypes, consistent with the pleiotropic nature of the clinical syndrome as a whole.

Original languageEnglish (US)
JournalCirculation Research
Volume96
Issue number10
StatePublished - May 27 2005
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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  • Cite this

    Shibayama, J., Paznekas, W., Seki, A., Taffet, S., Jabs, E. W., Delmar, M., & Musa, H. (2005). Functional characterization of connexin43 mutations found in patients with oculodentodigital dysplasia. Circulation Research, 96(10).