title: Effect of temperature on protein and immunoglobulin synthesis and secretion in two mouse myeloma cell lines.
abstract: Protein synthesis in differentiated MOPC-21 and MPC-11 mouse myeloma cells was studied to determine the basis for the differences in the temperature and actinomycin D sensitivity of translation between non-differentiated mouse L-cells and differentiated rabbit reticulocytes. The temperature dependence of total protein synthesis was similar to that of L-cells and reticulocytes, being biphasic in Arrhenius plots with apparent activation energies of approximately 25 and 42 kcal/mol, above and below 25 degress C. The dependence of the secretion process was different since it was not biphasic, having a single activation energy of about 22 kcal/mol. Myeloma polysomes were like L-cell polysomes in their response to lower temperature and reached a minimum level of 50% at 15 degress C. This response was also found for the specific polysomes synthesizing the IgG H- and L-chains. In the presence of actinomycin D, myeloma polysomes declined exponentially with a half-life of approximately 6 hours. These two L-cell-like responses were not found in reticulocytes. Translation of both the IgG mRNAs and the non-IgG mRNAs was reduced by lower temperatures and actinomycin D, even though the L-chain mRNA was slightly more resistant, suggesting that this mRNA is slightly more efficient. The results of these experiments suggest that the translational differences between L-cells and reticulocytes are not mRNA dependent, but are cell type differences.
mesh_terms: D000818:Animals; D002460:Cell Line; D003609:Dactinomycin / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D007074:Immunoglobulin G / Q000096:biosynthesis*; D051379:Mice; D009101:Multiple Myeloma / Q000378:metabolism*; D009194:Myeloma Proteins / Q000096:biosynthesis*; D009374:Neoplasms, Experimental / Q000378:metabolism; D014176:Protein Biosynthesis; D012270:Ribosomes / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature
chemical_list: D007074:Immunoglobulin G; D009194:Myeloma Proteins; D003609:Dactinomycin; D012965:Sodium Chloride