The half-life of immunoglobulin mRNA increases during B-cell differentiation: a possible role for targeting to membrane-bound polysomes.
The increase in abundance of immunoglobulin heavy-chain (IgH) mRNA that accompanies development of a B cell into a plasma cell is mainly due to post-transcriptional events. By constructing mu genes, whose expression is under inducible control, we determined the half-life of pulsed mu transcripts to be approximately 20 hr in plasmacytoma hosts and approximately 3 hr in B-cell lymphomas. Interestingly, a mu gene with a mutated signal sequence that is found on free (rather than membrane-bound) polysomes decays in the plasmacytoma host with a shortened half-life of 3 hr. Thus, a change in the turnover rate of IgH mRNA plays an important role in the cell-type specificity of immunoglobulin gene expression; this change may be a consequence of the fact that IgH mRNA is located in the membrane-bound polysome fraction.
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation; D006207:Half-Life; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D051379:Mice; D009154:Mutation; D010950:Plasma Cells / Q000276:immunology / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*
D007143:Immunoglobulin Heavy Chains; D012333:RNA, Messenger