摘要
Most eukaryotic mRNAs are translated in a cap-dependent fashion;however,under stress conditions,the cap-independent translation driven by internal ribosomal entry sites(IRESs)can serve as an alternative mechanism for protein production.Many IRESs have been discovered from viral or cellular mRNAs to promote ribosome assembly and initiate translation by recruiting different trons-acting factors.Although the mechanisms of translation initiation driven by viral IRESs are relatively well understood,the existence of cellular IRESs is still under debate due to the limitations of translation reporter systems used to assay IRES activities.A recent screen identified>1000 putative IRESs from viral and human mRNAs,expanding the scope and mechanism for capindependent translation.Additionally,a large number of circular RNAs lacking free ends were identified in eukaryotic cells,many of which are found to be translated through IRESs.These findings suggest that IRESs may play a previously unappreciated role in driving translation of the new type of mRNA,implying a hidden proteome produced from cap-independent translation.
基金
This work is supported by the National Natural Science Foundation of China(31570823,31661143031,and 31730110 to Z.W.,91753135 and 31870814 to Y.Y.)
Z.W.is also supported by the CAS Pioneer 100-Talent Program(type A).Y.Y.is also sponsored by the Youth Innovation Promotion Association CAS and Shanghai Scienee and Technology Committee Rising-Star Program(19QA1410500).
