Regulation of Ig gene expression in normal lymphocytes. I. The half‐life of secreted μ chain mRNA differs from that of membrane μ chain mRNA in resting and activated B cells

Resting and activated B lymphocytes were used to study the stability of mu-specific precursor and mature mRNA. Resting cells which predominantly process the mu precursor towards micron do so rather slowly as reflected in a precursor half-life (T1/2) of 1-2 h. The small amount of secreted mu chain mRNA is fairly stable (T1/2 approximately 8 h) compared to membrane mu chain (T1/2 approximately 4 h). After activation the precursor processing is very fast (T1/2 approximately 10 min) and the stability of mu2, which now predominates, increases (T1/2 approximately 16 h) while the half-life of micron remains at about 4 h. The data indicate that normal B cells regulate mu-specific mRNA stability differently from tumor cells of the B cell lineage.