A connexin‐32 mutation associated with Charcot‐Marie‐Tooth disease does not affect channel formation in oocytes

Abstract

Members of the connexin family differ most in their carboxy‐termini, both with respect to sequence and length. In order to assess the contribution of this region to channel function, a series of carboxy‐terminal deletion mutants were tested in the paired‐oocyte expression system. Connexin‐32 can be truncated by 64 amino acids without detectable loss of its known channel properties. Removal of additional amino acids results in a progressive loss of function over a stretch of 4 amino acids. In addition to this effect of length the charge of the carboxy‐terminus appears to be another determinant of channel function. One of the fully functional deletion mutants, carrying a stop codon after amino acid‐219, had been reported to be associated with Charcot‐Marie‐Tooth disease. The implications of this finding are discussed.