Target mRNAs are repressed as efficiently by microRNA-binding sites in the 5' UTR as in the 3' UTR.

@article{citeulike:1354226, abstract = {In animals, microRNAs (miRNAs) bind to the 3' UTRs of their target mRNAs and interfere with translation, although the exact mechanism of inhibition of protein synthesis remains unclear. Functional miRNA-binding sites in the coding regions or 5' UTRs of endogenous mRNAs have not been identified. We studied the effect of introducing miRNA target sites into the 5' UTR of luciferase reporter mRNAs containing internal ribosome entry sites (IRESs), so that potential steric hindrance by a microribonucleoprotein complex would not interfere with the initiation of translation. In human HeLa cells, which express endogenous let-7a miRNA, the translational efficiency of these IRES-containing reporters with 5' let-7 complementary sites from the Caenorhabditis elegans lin-41 3' UTR was repressed. Similarly, the IRES-containing reporters were translationally repressed when human Ago2 was tethered to either the 5' or 3' UTR. Interestingly, the method of DNA transfection affected our ability to observe miRNA-mediated repression. Our results suggest that association with any position on a target mRNA is mechanistically sufficient for a microribonucleoprotein to exert repression of translation at some step downstream of initiation.}, address = {Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06536.}, author = {Lytle, J Robin R. and Yario, Therese A A. and Steitz, Joan A A. }, citeulike-article-id = {1354226}, doi = {10.1073/pnas.0703820104}, issn = {0027-8424}, journal = {Proc Natl Acad Sci U S A}, keywords = {ch1, ch6, mirna, rnai}, month = {May}, posted-at = {2007-06-04 13:25:18}, priority = {2}, title = {Target mRNAs are repressed as efficiently by microRNA-binding sites in the 5' UTR as in the 3' UTR.}, url = {http://dx.doi.org/10.1073/pnas.0703820104}, year = {2007} }

TY - JOUR ID - citeulike:1354226 L3 - citeulike-article-id:1354226 TI - Target mRNAs are repressed as efficiently by microRNA-binding sites in the 5' UTR as in the 3' UTR. JF - Proc Natl Acad Sci U S A AD - Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06536. SN - 0027-8424 N2 - In animals, microRNAs (miRNAs) bind to the 3' UTRs of their target mRNAs and interfere with translation, although the exact mechanism of inhibition of protein synthesis remains unclear. Functional miRNA-binding sites in the coding regions or 5' UTRs of endogenous mRNAs have not been identified. We studied the effect of introducing miRNA target sites into the 5' UTR of luciferase reporter mRNAs containing internal ribosome entry sites (IRESs), so that potential steric hindrance by a microribonucleoprotein complex would not interfere with the initiation of translation. In human HeLa cells, which express endogenous let-7a miRNA, the translational efficiency of these IRES-containing reporters with 5' let-7 complementary sites from the Caenorhabditis elegans lin-41 3' UTR was repressed. Similarly, the IRES-containing reporters were translationally repressed when human Ago2 was tethered to either the 5' or 3' UTR. Interestingly, the method of DNA transfection affected our ability to observe miRNA-mediated repression. Our results suggest that association with any position on a target mRNA is mechanistically sufficient for a microribonucleoprotein to exert repression of translation at some step downstream of initiation. KW - ch1 KW - ch6 KW - mirna KW - rnai AU - Lytle, J Robin AU - Yario, Therese A AU - Steitz, Joan A PY - 2007/05/29/ UR - http://dx.doi.org/10.1073/pnas.0703820104 ER -