高效翻译绕过由 mRNA 结构和新生肽指定的非编码核苷酸。

High-efficiency translational bypassing of non-coding nucleotides specified by mRNA structure and nascent peptide.

机构信息

Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.

1] Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany [2] Molecular and Radiation Biophysics Department, B.P. Konstantinov Petersburg Nuclear Physics Institute, 188300 Gatchina, Russia, and St. Petersburg State Polytechnical University, Polytechnicheskaya 29, 195251 St. Petersburg, Russia.

出版信息

Nat Commun. 2014 Jul 21;5:4459. doi: 10.1038/ncomms5459.

DOI:10.1038/ncomms5459

PMID:25041899

Abstract

The gene product 60 (gp60) of bacteriophage T4 is synthesized as a single polypeptide chain from a discontinuous reading frame as a result of bypassing of a non-coding mRNA region of 50 nucleotides by the ribosome. To identify the minimum set of signals required for bypassing, we recapitulated efficient translational bypassing in an in vitro reconstituted translation system from Escherichia coli. We find that the signals, which promote efficient and accurate bypassing, are specified by the gene 60 mRNA sequence. Systematic analysis of the mRNA suggests unexpected contributions of sequences upstream and downstream of the non-coding gap region as well as of the nascent peptide. During bypassing, ribosomes glide forward on the mRNA track in a processive way. Gliding may have a role not only for gp60 synthesis, but also during regular mRNA translation for reading frame selection during initiation or tRNA translocation during elongation.

摘要

噬菌体 T4 的基因产物 60（gp60）是由核糖体绕过 50 个核苷酸的非编码 mRNA 区域而从一个不连续的阅读框中作为一条单链多肽合成的。为了鉴定绕过所需的最小信号集，我们在体外重建的大肠杆菌翻译系统中重新进行了有效的翻译旁路。我们发现，促进有效和准确旁路的信号是由基因 60 mRNA 序列指定的。对 mRNA 的系统分析表明，非编码缺口区域上下游的序列以及新生肽也有意外的贡献。在旁路过程中，核糖体以连续的方式在 mRNA 轨道上向前滑行。滑行不仅可能对 gp60 合成起作用，而且在起始时的阅读框选择或延伸过程中的 tRNA 易位期间，对常规 mRNA 翻译也起作用。