Mechanism of inhibition of eukaryotic translational initiation by the trinucleotide ApUpG

FEBS Letters

Wagner, Thomas¹  Gross, Martin²  Sigler, Paul B.¹ 

[1] Departments of Biochemistry & Molecular Biology, 920 E. 58th Street, Chicago, IL 60637, USA;Pathology, The University of Chicago, 920 E. 58th Street, Chicago, IL 60637, USA

关键词: Reticulocyte lysate;    Protein synthesis;    Initiation codon;    Oligoribonucleotide;    80 S complex;   

DOI  :  10.1016/0014-5793(89)80708-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

ApUpG, the oligoribonucleotide homologous to the initiation codon, as well as the tetranucleotides ApUpGpA and ApUpGpG block initiation of protein synthesis in the rabbit reticulocyte lysate. These oligonucleotides are recognized as translational initiation sites by the ribosomes, leading to a very large accumulation of complete, but inactive, 80 S initiation complexes, containing methionylated initiator tRNA and ApUpG in a 1:1 stoichiometry. ApUpG appears to inhibit by competing with endogenous globin mRNA for 80 S ribosomal couples, since the inhibition of protein synthesis by ApUpG can be largely relieved by increasing the globin mRNA. The 80 S · Met-tRNA_i ^Met · ApUpG complexes are not formed in the absence of hemin, demonstrating that their formation requires the active recycling of eukaryotic initiation factor 2. In addition the trinucleotide correctly directs the Met-tRNA_i ^Met into the ribosomal donor site, since the methionyl residue is puromycin-reactive.

【 授权许可】

Unknown