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microRNA-9 targets the long non-coding RNA MALAT1 for degradation in the nucleus.

Leucci E, Patella F, Waage J, Holmstrøm K, Lindow M, Porse B, Kauppinen S, Lund AH - Sci Rep (2013)

Bottom Line: microRNAs regulate the expression of over 60% of protein coding genes by targeting their mRNAs to AGO2-containing complexes in the cytoplasm and promoting their translational inhibition and/or degradation.There is little evidence so far for microRNA-mediated regulation of other classes of non-coding RNAs.Our findings reveal a novel direct regulatory link between two important classes of non-coding RNAs, miRs and lncRNAs, and advance our understanding of microRNA functions.

View Article: PubMed Central - PubMed

Affiliation: 1] Biotech Research and Innovation Centre and Centre for Epigenetics, University of Copenhagen, Denmark [2].

ABSTRACT
microRNAs regulate the expression of over 60% of protein coding genes by targeting their mRNAs to AGO2-containing complexes in the cytoplasm and promoting their translational inhibition and/or degradation. There is little evidence so far for microRNA-mediated regulation of other classes of non-coding RNAs. Here we report that microRNA-9 (miR-9) regulates the expression of the Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT-1), one of the most abundant and conserved long non-coding RNAs. Intriguingly, we find that miR-9 targets AGO2-mediated regulation of MALAT1 in the nucleus. Our findings reveal a novel direct regulatory link between two important classes of non-coding RNAs, miRs and lncRNAs, and advance our understanding of microRNA functions.

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MALAT1 expression is regulated by miRNA (a) Cells were transfected with a scramble control or a pool of siRNA against AGO2. Western blot for AGO2 shows the efficiency of AGO2 knock down in U87MG and L428 cells. The lower and the upper panel (for both cell lines) derive from the same gel, only the membrane was split in two to perform the incubation with the antibody. A full picture of the gel can be found in the supplementary informations. (b) qPCR shows MALAT1 stabilization upon knock-down of AGO2 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3). (c) Cells were transfected with an 8-mer against miR-9 or a scrambled 8-mer. qPCR shows MALAT1 stabilization upon inhibition of miR-9 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3).
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f2: MALAT1 expression is regulated by miRNA (a) Cells were transfected with a scramble control or a pool of siRNA against AGO2. Western blot for AGO2 shows the efficiency of AGO2 knock down in U87MG and L428 cells. The lower and the upper panel (for both cell lines) derive from the same gel, only the membrane was split in two to perform the incubation with the antibody. A full picture of the gel can be found in the supplementary informations. (b) qPCR shows MALAT1 stabilization upon knock-down of AGO2 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3). (c) Cells were transfected with an 8-mer against miR-9 or a scrambled 8-mer. qPCR shows MALAT1 stabilization upon inhibition of miR-9 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3).

Mentions: We next investigated whether MALAT1 expression is under the control of microRNAs by knocking down AGO2 in the L428 and U87MG cell lines (Fig. 2a). We observed a significant increase in MALAT1 expression in AGO2 KD cells (Fig. 2b) whereas, as expected, miR-9 stability is impaired by AGO2 knockdown (supplementary figure 2a). Importantly, miR-9 inhibition also resulted in a significant increase in MALAT1 levels (Fig. 2c, supplementary figure 2b) in both cell lines. Moreover, miR-9 overexpression resulted in a significant down-regulation of MALAT1 (supplementary figure 2c). Moreover, miR-9 overexpression resulted in a modest, but significant down-regulation of MALAT1 (supplementary figure 2b), most likely because both cell lines already express high levels of miR-915. Together these data indicate that miR-9 directly regulates the level of MALAT1.


microRNA-9 targets the long non-coding RNA MALAT1 for degradation in the nucleus.

Leucci E, Patella F, Waage J, Holmstrøm K, Lindow M, Porse B, Kauppinen S, Lund AH - Sci Rep (2013)

MALAT1 expression is regulated by miRNA (a) Cells were transfected with a scramble control or a pool of siRNA against AGO2. Western blot for AGO2 shows the efficiency of AGO2 knock down in U87MG and L428 cells. The lower and the upper panel (for both cell lines) derive from the same gel, only the membrane was split in two to perform the incubation with the antibody. A full picture of the gel can be found in the supplementary informations. (b) qPCR shows MALAT1 stabilization upon knock-down of AGO2 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3). (c) Cells were transfected with an 8-mer against miR-9 or a scrambled 8-mer. qPCR shows MALAT1 stabilization upon inhibition of miR-9 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3756333&req=5

f2: MALAT1 expression is regulated by miRNA (a) Cells were transfected with a scramble control or a pool of siRNA against AGO2. Western blot for AGO2 shows the efficiency of AGO2 knock down in U87MG and L428 cells. The lower and the upper panel (for both cell lines) derive from the same gel, only the membrane was split in two to perform the incubation with the antibody. A full picture of the gel can be found in the supplementary informations. (b) qPCR shows MALAT1 stabilization upon knock-down of AGO2 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3). (c) Cells were transfected with an 8-mer against miR-9 or a scrambled 8-mer. qPCR shows MALAT1 stabilization upon inhibition of miR-9 in U87MG and L428. p-values were calculated using a t-test. Bars show mean +/− SEM (n = 3).
Mentions: We next investigated whether MALAT1 expression is under the control of microRNAs by knocking down AGO2 in the L428 and U87MG cell lines (Fig. 2a). We observed a significant increase in MALAT1 expression in AGO2 KD cells (Fig. 2b) whereas, as expected, miR-9 stability is impaired by AGO2 knockdown (supplementary figure 2a). Importantly, miR-9 inhibition also resulted in a significant increase in MALAT1 levels (Fig. 2c, supplementary figure 2b) in both cell lines. Moreover, miR-9 overexpression resulted in a significant down-regulation of MALAT1 (supplementary figure 2c). Moreover, miR-9 overexpression resulted in a modest, but significant down-regulation of MALAT1 (supplementary figure 2b), most likely because both cell lines already express high levels of miR-915. Together these data indicate that miR-9 directly regulates the level of MALAT1.

Bottom Line: microRNAs regulate the expression of over 60% of protein coding genes by targeting their mRNAs to AGO2-containing complexes in the cytoplasm and promoting their translational inhibition and/or degradation.There is little evidence so far for microRNA-mediated regulation of other classes of non-coding RNAs.Our findings reveal a novel direct regulatory link between two important classes of non-coding RNAs, miRs and lncRNAs, and advance our understanding of microRNA functions.

View Article: PubMed Central - PubMed

Affiliation: 1] Biotech Research and Innovation Centre and Centre for Epigenetics, University of Copenhagen, Denmark [2].

ABSTRACT
microRNAs regulate the expression of over 60% of protein coding genes by targeting their mRNAs to AGO2-containing complexes in the cytoplasm and promoting their translational inhibition and/or degradation. There is little evidence so far for microRNA-mediated regulation of other classes of non-coding RNAs. Here we report that microRNA-9 (miR-9) regulates the expression of the Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT-1), one of the most abundant and conserved long non-coding RNAs. Intriguingly, we find that miR-9 targets AGO2-mediated regulation of MALAT1 in the nucleus. Our findings reveal a novel direct regulatory link between two important classes of non-coding RNAs, miRs and lncRNAs, and advance our understanding of microRNA functions.

Show MeSH
Related in: MedlinePlus