Evidence for sequential expression of multiple AMP deaminase isoforms during skeletal muscle development.

AMP deaminase (myoadenylate deaminase; EC 3.5.4.6) is an integral part of the myofibril in skeletal muscle, and this enzyme plays an important role in energy metabolism in this tissue. We report here the identification of three AMP deaminase isoforms during skeletal muscle development in the rat. An embryonic isoform is expressed in the developing hindlimb of the rat between 7 and 14 days of gestation. This isoform is not unique to skeletal muscle or the embryo as it is also expressed in many nonmuscle tissues of the perinatal and adult rat. A perinatal isoform of AMP deaminase that is restricted to skeletal muscle is produced 4-6 days before birth and persists for 2-3 weeks of postnatal life. An adult, skeletal muscle-specific isoform of AMP deaminase appears at birth and reaches maximal levels after 3 weeks of postnatal development. We conclude from these studies there is a developmentally controlled program that leads to the sequential expression of AMP deaminase isoforms during the transition from embryonic to adult skeletal muscle.