Neuromuscular function and polymorphism of the acetylcholine receptor gamma gene.

Examination of inbred and wild mice has shown that the gene coding for the acetylcholine receptor gamma subunit is polymorphic and the polymorphism correlates with differences in neuromuscular function tested by two different methods. Polymorphism of the AChR gamma gene was demonstrated after digestion of genomic DNA with Pstl and Xbal. These two restriction enzymes demonstrated RFLP patterns specific for C57Bl/6J (PSXS) and C3H/HeJ (PRXR) mice, respectively. Examination of F1 (C3H/HeJ x C57Bl/6J) and F2 hybrid populations, and other murine inbred strains, showed the inheritance and strain specificity of the RFLPs. Testing wild mice demonstrated that the PSXS form of the AChR gamma gene is the most common in the wild. The AChR gamma and AChR delta subunits are closely linked and carried on the same chromosome as several contractile proteins. Because these genes are essential for correct neuromuscular development and activity, we investigated the possibility that the observed AChR gamma polymorphisms mark a haplotype which correlates with variations in neuromuscular function. Analysis of exercise times showed a correlation between AChR gamma polymorphism and neuromuscular function. To our knowledge, this is the first description of AChR polymorphism cosegregating with variations in neuromuscular function.