Characterization of an inhibitor of protein synthesis initiation from mouse erythroleukemia cells.
This study describes the partial purification of a translational inhibitor from mouse erythroleukemia (MEL) cells. It is present in MEL cells induced to erythroid differentiation and in uninduced cells in approximately equal amounts. The inhibitor blocks initiation but not elongation of in vitro protein synthesis in the rabbit reticulocyte lysate and in extracts prepared from induced or uninduced MEL cells. Nuclease-resistance, heat-sensitivity and the chromatographic behaviour of the inhibitor indicate that it is a protein with a relative molecular mass of approx. (45-70).10(3). The inhibitor has no eIF-2 alpha phosphorylating activity and does not affect the formation of the ternary complex [eIF-2.GTP.Met-tRNAf] nor the binding of Met-tRNAf to the 40 S ribosomal subunit. The inhibitor interferes with the binding of mRNA to the 43 S preinitiation complex, independent of the presence of the m7GTP cap of the mRNA.
Bader
M
M
Institut für Biologie III, Freiburg, F.R.G.
Sarre
T F
TF
D000818:Animals; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D005914:Globins / Q000235:genetics; D006358:Hot Temperature; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism*; D051379:Mice; D008836:Micrococcal Nuclease / Q000494:pharmacology; D008970:Molecular Weight; D010441:Peptide Chain Elongation, Translational / Q000187:drug effects; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects; D010766:Phosphorylation; D014176:Protein Biosynthesis / Q000187:drug effects*; D011500:Protein Synthesis Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D012315:RNA Caps / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012358:RNA, Transfer, Met / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D014407:Tumor Cells, Cultured
D015852:Eukaryotic Initiation Factor-2; D011500:Protein Synthesis Inhibitors; D012315:RNA Caps; D012333:RNA, Messenger; D012358:RNA, Transfer, Met; D005914:Globins; D008836:Micrococcal Nuclease