MicroRNA Inhibition of Translation Initiation in Vitro by Targeting the Cap-Binding Complex eIF4F Nahum Sonenberg et al. Science, September 2007 Presentation by Ansuman sahoo Advanced Mol. Bio Class

Core Features of miRNA and siRNA Silencing

Fig. 1. Repression of protein synthesis by let-7 miRNA in an ascites extract. G Mathonnet et al. Science 2007;317: Published by AAAS

Fig. 2. let-7 miRNA inhibits translation without affecting mRNA stability in an ascites extract. G Mathonnet et al. Science 2007;317: Published by AAAS

Fig. 3. let-7 miRNA inhibits ribosome binding. G Mathonnet et al. Science 2007;317: Published by AAAS

3’ Cap Dependent Translation Initiation

IRES Mediated Translation

Fig. 4. let-7 miRNA inhibits cap-dependent, but not cap-independent, translation in an ascites extract. G Mathonnet et al. Science 2007;317: Published by AAAS

Figure : Possible Mechanisms of miRISC-Mediated Repression Nonrepressed mRNAs recruit initiation factors and ribosomal subunits and form circularized structures that enhance translation (top). When miRISCs bind to mRNAs, they can repress initiation at the... Richard W. Carthew, Erik J. Sontheimer Origins and Mechanisms of miRNAs and siRNAs Cell, Volume 136, Issue 4, 2009,

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