Hironao Wakabayashi, Mingyi Zhu, Elizabeth J Grayhack, David H Mathews, Dmitri N Ermolenko
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引用次数: 0
Abstract
During eukaryotic translation initiation, the small (40S) ribosomal subunit is recruited to the 5' cap and subsequently scans the 5' untranslated region (5' UTR) of mRNA in search of the start codon. The molecular mechanism of mRNA scanning remains unclear, particularly the requirement for and identity of a translocase. Here, using GFP reporters in Saccharomyces cerevisiae, we show that order-of-magnitude variations in the length of unstructured 5' UTRs have only modest effects on protein synthesis, whereas structured 5' UTRs strongly inhibit translation. Thus, when not hindered by secondary structure, mRNA scanning is not rate limiting. Loss-of-function mutations in eIF4A, Ded1, and Slh1 reveal that these translational helicases are dispensable for mRNA scanning. Our data suggest that one-dimensional diffusion predominately enables 40S movement along the 5' UTR during mRNA scanning.
期刊介绍：
RNA is a monthly journal which provides rapid publication of significant original research in all areas of RNA structure and function in eukaryotic, prokaryotic, and viral systems. It covers a broad range of subjects in RNA research, including: structural analysis by biochemical or biophysical means; mRNA structure, function and biogenesis; alternative processing: cis-acting elements and trans-acting factors; ribosome structure and function; translational control; RNA catalysis; tRNA structure, function, biogenesis and identity; RNA editing; rRNA structure, function and biogenesis; RNA transport and localization; regulatory RNAs; large and small RNP structure, function and biogenesis; viral RNA metabolism; RNA stability and turnover; in vitro evolution; and RNA chemistry.
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