REGULATION OF IG GENE-EXPRESSION IN NORMAL LYMPHOCYTES .1. THE HALF-LIFE OF SECRETED MU-CHAIN MESSENGER-RNA DIFFERS FROM THAT OF MEMBRANE MU-CHAIN MESSENGER-RNA IN RESTING AND ACTIVATED B-CELLS

Resting and activated B lymphocytes were used to study the stability of μ‐specific precursor and mature mRNA. Resting cells which predominantly process the μ precursor towards μm do so rather slowly as reflected in a precursor half‐life (T1/2) of 1‐2 h. The small amount of secreted μ chain mRNA is fairly stable (T1/2 ≈ 8 h) compared to membrane μ chain (T1/2 ≈ 4 h). After activation the precursor processing is very fast (T1/2 ≈ 10 min) and the stability of μ2, which now predominates, increases (T1/2 ≈ 16 h) while the half‐life of μm remains at about 4 h. The data indicate that normal B cells regulate μ‐specific mRNA stability differently from tumor cells of the B cell lineage. Copyright © 1990 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim