A connexin-32 mutation associated with Charcot-Marie-Tooth disease does not affect channel formation in oocytes.
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.
Rabadan-Diehl
C
C
Department of Physiology, University of Miami, School of Medicine, FL 33101.
Dahl
G
G
Werner
R
R
D000595:Amino Acid Sequence; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics*; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D017629:Gap Junctions / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes; D000097002:Gap Junction beta-1 Protein
D017630:Connexins; D000097002:Gap Junction beta-1 Protein