Exclusion of the beta-subunit of type II calmodulin kinase for the wobbler spinal muscular atrophy gene.

The wobbler mouse (wr) is an attractive model for studying motor neuron disease but the genetic defect is unknown. The beta-subunit of calmodulin kinase II (beta-CaMK II) is a good candidate for the wr mutation because of its chromosomal localization and tissue distribution. In this report, we found normal levels of CaM KII mRNA and enzyme activity making it highly unlikely that a mutation in the beta-CaM KII gene is the cause of the wr phenotype.