The postnatal accumulation of S-100 protein in mouse central nervous system. Modulation of protein synthesis and degradation

Abstract

A study was made of the rates of synthesis and degradation of the S-100 protein during the postnatal development of the mouse central nervous system. From 3 to 15 days the S-100 concentration remains constant. From 16 to 21 days S-100 accumulates, rising from about 4 μg per brain to a level of approximately 16 μg per brain. From 21 days to 10 mo of age, the S-100 concentration remains constant. The zero-order rate constant of synthesis and the first-order rate constant for degradation were determined during these periods by means of isotope incorporation studies. Initiation of accumulation is accompanied by an increase in both rates of synthesis and degradation. During accumulation of S-100 the rate of degradation remains constant while the rate of synthesis continually increases. Cessation of accumulation is caused by a decrease in both rates of synthesis and degradation. Therefore the control of the accumulation of this protein during mouse central nervous system development is a result of modulation of both rates of synthesis and degradation.