Dataset Information

Specificity and functionality of microRNA inhibitors.

ABSTRACT:

Background

Micro(mi)RNAs regulate gene expression through translational attenuation and messenger (m)RNA degradation, and are associated with differentiation, homeostasis and disease. Natural miRNA target recognition is determined primarily by perfect complementarity in a seed region (nucleotide positions 2 to 7) with additional interactions contributing in a sequence- and target-specific manner. Synthetic miRNA target analogs, which are fully complementary, chemically modified oligonucleotides, have been used successfully to inhibit miRNA function.

Results

In this paper, we present a first systematic study to evaluate the effect of mismatches in the target site on synthetic inhibitor activity. Panels of miRNA inhibitors containing two-nucleotide mismatches across the target site were tested against three miRNAs (miR-21, miR-22 and miR-122). The results showed that the function of inhibitors vary as mismatch positions in the inhibitors change.

Conclusions

The data indicate that features important for natural miRNA target recognition (such as seed region complementarity) are also important for inhibitor functionality. In addition, base pairing at a second, more 3' region appears to be equally important in determining the efficacy of synthetic inhibitors. Considering the importance of these inhibitor regions and the expression of closely related miRNA sequences will enable researchers to interpret results more accurately in future experiments.

SUBMITTER: Robertson B

PROVIDER: S-EPMC2864222 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

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Publications

Specificity and functionality of microRNA inhibitors.

Robertson Barbara B Dalby Andrew B AB Karpilow Jon J Khvorova Anastasia A Leake Devin D Vermeulen Annaleen A

Silence 20100401 1

<h4>Background</h4>Micro(mi)RNAs regulate gene expression through translational attenuation and messenger (m)RNA degradation, and are associated with differentiation, homeostasis and disease. Natural miRNA target recognition is determined primarily by perfect complementarity in a seed region (nucleotide positions 2 to 7) with additional interactions contributing in a sequence- and target-specific manner. Synthetic miRNA target analogs, which are fully complementary, chemically modified oligonucl ...[more]

PMID: 20359337

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Project description:Using a three-pronged MS-based proteomic approach, we assessed the mode-of-action of four clinically-relevant tyrosine kinase inhibitors in an epithelial cancer cell line. Here we defined the: (I) semi-quantitative tyrosine kinome; (II) drug interactome; and (III) drug-induced effects on the tyrosine signalome. We first examined the entire proteome and kinome profile expressed in the A431 cell line, and determined the relative abundance of all possible protein targets of the tyrosine kinase inhibitors. We therefore utilized a ‘shot-gun’ approach that involved a multidimensional separation-based proteomic strategy. To ensure maximal protein identification, we reduced sample complexity by strong cation exchange (SCX) chromatography, and analyzed all fractions by LC-MS/MS. To determine the direct targets of the four selected TKIs, we subjected the proteins extracted from the A431 cancer cell line to drug-coupled affinity matrices. By comparing the pull-down results from a lysate with a second identical lysate to which 20 uM of the inhibitor had been added to block binding to the beads, we were able to identify selective binding interactors using LC-MS/MS. This differential affinity pull-downs approach allowed us to also quantitatively evaluate the binding affinity of the tyrosine kinases to each of the drugs. To evaluate the global tyrosine phosphorylation dynamics that occurs in A431 cells upon treatment with each of the four inhibitors, phosphotyrosine peptides were enriched and identified by quantitative mass spectrometry. For this purpose, we treated the cells with each inhibitor for 2 h at appropriate concentrations adopted from reported studies. Cells were lysed, and the proteins digested with the proteases Lys-C and trypsin. To allow quantitation of the phosphorylated peptides originating from the three different peptide pools (control/imatinib/dasatinib or control/bosutinib/nilotinib), we used stable isotope dimethyl labeling. Subsequently, tyrosine-phosphorylated peptides were enriched by immunoprecipitation and analyzed by LC-MS/MS.

Dataset Information

Specificity and functionality of microRNA inhibitors.

Background

Results

Conclusions

Publications

Specificity and functionality of microRNA inhibitors.

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