title: Regulation of the utilization of mRNA for eucaryotic elongation factor Tu in Friend erythroleukemia cells.
abstract: When Friend erythroleukemia cells were allowed to grow to stationary phase (2 X 10(6) to 3 X 10(6) cells per ml), approximately 60% of the mRNA for eucaryotic elongation factor Tu (eEF-Tu) sedimented at less than or equal to 80S, and most of the remaining factor mRNA was associated with small polysomes. Under the same growth conditions, greater than 90% of the mRNA for eucaryotic initiation factor 4A remained associated with polysomes. The association of eEF-Tu mRNA with polysomes changed dramatically when stationary-phase cells were treated with fresh medium. After 1 h in fresh medium, approximately 90% of eEF-Tu mRNA in Friend cells was found in heavy polysomes. Associated with the shift of eEF-Tu mRNA into heavy polysomes, we found at least a 2.6-fold increase in the synthesis of eEF-Tu in vivo as well as a remarkable 40% decrease in the total amount of eEF-Tu mRNA per cell. Our data raise the possibility that eEF-Tu mRNA that has accumulated in ribonucleoprotein particles in stationary-phase cells is degraded rather than reutilized for eEF-Tu synthesis.
mesh_terms: D000818:Animals; D002451:Cell Compartmentation; D002453:Cell Cycle; D002478:Cells, Cultured; D003470:Culture Media; D003513:Cycloheximide / Q000494:pharmacology; D003593:Cytoplasm / Q000502:physiology; D003609:Dactinomycin / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006133:Growth Substances / Q000494:pharmacology; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics; D051379:Mice; D010444:Peptide Elongation Factor Tu / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D012261:Ribonucleoproteins / Q000378:metabolism
chemical_list: D003470:Culture Media; D006133:Growth Substances; D012333:RNA, Messenger; D012261:Ribonucleoproteins; C026452:messenger ribonucleoprotein; D003609:Dactinomycin; D003513:Cycloheximide; D010444:Peptide Elongation Factor Tu