Nerve-dependent expression of c-myc protein during forelimb regeneration of Xenopus laevis froglets

The consequences of denervation on the expression of c-myc protein have been analyzed on the regenerating forelimb of young froglets of Xenopus laevis. The level of c-myc expression, low in control limbs and enhanced in the regenerate, is transiently increased after a three-hour total denervation. For this protein, the level of expression is not a function of the quantity of nerve in the regenerate. Four days after denervation, c-myc signal is back to its base level observed in the regenerate. A different pattern of expression is obtained for an S phase marker (PCNA protein) taken as a control in the same experimental conditions. The data presented here show that the nervous system normally exerts a negative control on the expression of c-myc and PCNA proteins in the limb regenerate of Xenopus.