Eukaryotic initiation factor 4GI is a poor substrate for HIV-1 proteinase.
Eukaryotic initiation factor (eIF) 4GI is efficiently cleaved during picornaviral replication. eIF4GI processing has also recently been observed during HIV-1 replication. We have compared the efficiency of eIF4GI proteolysis in rabbit reticulocyte lysates during translation of mRNAs encoding the foot-and-mouth disease virus leader proteinase (L(pro)) or the HIV-1 proteinase (HIV-1(pro)). L(pro) cleaved 50% eIF4GI within 12 min whereas HIV-1(pro) required 4 h; the concentrations were 2 pg/microl (0.1 nM) for L(pro) and 60 pg/microl (2.66 nM) for HIV-1(pro). HIV-1(pro) processing of eIF4GI is therefore not quantitatively analogous to that of L(pro), suggesting that the primary function of eIF4GI cleavage in HIV-1 replication may not be protein synthesis inhibition.
Schlick
Petra
P
Institute for Medical Biochemistry, Division of Biochemistry, University of Vienna, Dr. Bohr-Gasse 9/3, A-1030 Vienna, Austria.
Skern
Tim
T
D004591:Electrophoresis, Polyacrylamide Gel; D039603:Eukaryotic Initiation Factor-4G; D016333:HIV Protease / Q000378:metabolism*; D015497:HIV-1 / Q000502:physiology; D006868:Hydrolysis; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D013379:Substrate Specificity; D014779:Virus Replication
C113920:EIF4G1 protein, human; D039603:Eukaryotic Initiation Factor-4G; D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D016333:HIV Protease