Supplementary MaterialsSupplemental Table 1. recurrent editing sites within human mRNAs, and
May 10, 2019
Supplementary MaterialsSupplemental Table 1. recurrent editing sites within human mRNAs, and many of these were located in 3 untranslated regions (UTRs). When these locations were screened against the list of currently-annotated miRNAs we discovered that editing caused a subset (~9%) to have significant alterations to mRNA complementarity. One Rabbit polyclonal to IL20RA miRNA in particular, miR-140C3p, is known to be misexpressed in many breast cancers, and we found that mRNA editing allowed this miRNA to Punicalagin distributor directly target the apoptosis inducing gene in MCF-7, but not in MDA-MB-231 cells. As these two cell lines are Punicalagin distributor known to have distinct characteristics in terms of morphology, invasiveness and physiological responses, we hypothesized that the differential RNA editing of in these two cell lines could contribute to their phenotypic differences. Indeed, we confirmed through western blotting that inhibiting miR-140C3p increases expression of the protein product in MCF-7, but not MDA-MB-231, and further that inhibition of miR-140C3p also increases cellular growth in MCF-7, but not MDA-MB-231. Broadly, these results suggest that the creation of miRNA targets may be an underappreciated function of ADAR and may help further elucidate the role of RNA editing in tumor pathogenicity. in MCF-7, but not MDA-MB-231. (A) Alignment of 21 nt segments of six RNA-Seq reads (three from each cell line) to a portion of the apoptosis inducing gene DFFA. Our edit identification algorithm identified an A-to-G edit site at basepair 10,460,668 on Chromosome 1, and corresponding reads mapping to that location were extracted and trimmed to 21 bp (edit site plus/minus 10 bp flanking regions). Edit location is outlined in red. The alignment was generated Punicalagin distributor via ClustalW . (B) Illustration showing complimentary base Punicalagin distributor pairing between the miR-140 seed (blue) and the DFFA gene in both cell lines. The edit site is indicated in green. 3.4. Inhibiting miR-140C3p Increases DFFA Expression in MCF-7 In order to determine if miR-140C3p directly regulates the endogenous expression of DFFA, we performed DFFA Western blots (Figure 6A) to examine the effects of introducing a specific miR-140C3p antagomir as compared to a non-specific control. Excitingly, although we found a marked increase of DFFA levels following miR-140C3p inhibition in MCF-7s (where a target site is created by ADAR deamination), we found no appreciable effect of inhibiting miR-140C3p in MDA-MB-231s (in which DFFA does not undergo deamination). Furthermore, qPCR analysis of DFFA expression found no effect on DFFA mRNA levels following miR-140C3p inhibition in either cell line (data not shown) confirming miR-140C3p regulates DFFA post transcriptionally. Open in a separate window Figure 6. Depletion of DFFA protein expression and the effect of miR-140C3p on cellular growth. (A) Representative blots for DFFA and -actin (loading control) are shown (n = 3). The miRNA is able to bind and regulate the gene in MCF-7, but not in MDA-MB-231 due the presence of an A-to-I edit. WT, wild type; Ctl, empty lipo transfection; Ant-140, miR-140 antagomir; Ant-Ctl, random antagomir. (B) Cell growth assay examining effects of transfecting a miR-140 inhibitor in both cell lines. Five microscopic fields randomly chosen from each assay were counted individually, and the statistical significance between treatment and control determined by regulations and further support the idea that miR-140C3p mediated downregulation of DFFA specifically in MCF-7 cells directly contributes to the characterized differences of these two cell lines in cellular growth. 4.?Discussion ADAR-mediated RNA editing is well characterized as having dramatic effects on a multitude of cellular processes [11,18,42,43]. However, the molecular mechanisms through which ADAR editing confers these effects remain largely undefined. That said, ADAR editing of miRNA transcripts has now been shown to affect their regulatory ability, in some cases leaving them unable to bind to their target transcripts and in others leading to unintended inhibition of new targets altogether [17,19,44]. To add to the relationship between A-to-I editing and miRNAs, we have now successfully.