NEURAL BC1 RNA IN MOUSE SKELETAL-MUSCLE IS A DENERVATION-INDUCED RNA WHOSE EXPRESSION IS DEVELOPMENTALLY-REGULATED

We detected neural BC1 RNA in mouse skeletal muscle, The level of BC1 RNA was high in the fetus, but it declined progressively to the adult level as development proceeded. These observations suggest that this R NA is involved in the prenatal development and differentiation of musc les. Although its developmental expression correlates with the fetal p eriod of polyneuronal innervation, BC1 RNA does not seem to play a dir ect role(s) in synaptogenesis, since its expression was not restricted to the neuromuscular junction. We also demonstrated that the BC1 RNA level in adult muscle was elevated after denervation, suggesting that changes in the activity of muscles or neural factors caused by axotomy , or both may result in BC1 RNA upregulation.