TY - JOUR
T1 - Initiation of translation at CUG, GUG, and ACG codons in mammalian cells
AU - Mehdi, Haider
AU - Ono, Etsuro
AU - Gupta, Kailash C.
PY - 1990/7/16
Y1 - 1990/7/16
N2 - Site-directed mutants of the ACG start codon of the C′ protein encoded in the polycistronic Sendai virus P/C mRNA revealed that CUG, GUG, and ACG codons initiated translation rather efficiently (10-30% of the AUG initiation) in COS-1 host cells. In addition, AUA and AUU codons initiated translation at about 5% efficiency, while UUG did not initiate translation. The sequence context of these start codons (purine residues at -3 and +4) was crucial in their recognition by the ribosome. The location of the non-AUG codons in the P/C mRNA did not play a role in its recognition by ribosomes. By using CUG, the most efficient non-AUG start codon, instead of the original ACG codon and inserting an additional upstream CUG codon in the P/C mRNA, the amount of the C′ protein was increased and a novel protein was synthesized. Syntheses of an increased level of C′ and the novel protein did not affect downstream initiations of the P and C proteins, suggesting that more ribosomes bind the mRNA than are actually utilized for initiation of translation.
AB - Site-directed mutants of the ACG start codon of the C′ protein encoded in the polycistronic Sendai virus P/C mRNA revealed that CUG, GUG, and ACG codons initiated translation rather efficiently (10-30% of the AUG initiation) in COS-1 host cells. In addition, AUA and AUU codons initiated translation at about 5% efficiency, while UUG did not initiate translation. The sequence context of these start codons (purine residues at -3 and +4) was crucial in their recognition by the ribosome. The location of the non-AUG codons in the P/C mRNA did not play a role in its recognition by ribosomes. By using CUG, the most efficient non-AUG start codon, instead of the original ACG codon and inserting an additional upstream CUG codon in the P/C mRNA, the amount of the C′ protein was increased and a novel protein was synthesized. Syntheses of an increased level of C′ and the novel protein did not affect downstream initiations of the P and C proteins, suggesting that more ribosomes bind the mRNA than are actually utilized for initiation of translation.
UR - http://www.scopus.com/inward/record.url?scp=0024999179&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024999179&partnerID=8YFLogxK
U2 - 10.1016/0378-1119(90)90085-6
DO - 10.1016/0378-1119(90)90085-6
M3 - Article
C2 - 2170233
AN - SCOPUS:0024999179
VL - 91
SP - 173
EP - 178
JO - Gene
JF - Gene
SN - 0378-1119
IS - 2
ER -