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Telomerase reverse transcriptase regulates microRNAs.

Lassmann T, Maida Y, Tomaru Y, Yasukawa M, Ando Y, Kojima M, Kasim V, Simon C, Daub CO, Carninci P, Hayashizaki Y, Masutomi K - Int J Mol Sci (2015)

Bottom Line: In humans, most microRNAs are transcribed by RNA polymerase II as long primary transcripts and processed by sequential cleavage of the two RNase III enzymes, DROSHA and DICER, into precursor and mature microRNAs, respectively.Although the fundamental functions of microRNAs in RNA silencing have been gradually uncovered, less is known about the regulatory mechanisms of microRNA expression.These results suggest that TERT regulates microRNAs at the very early phases in their biogenesis, presumably through non-telomerase mechanism(s).

View Article: PubMed Central - PubMed

Affiliation: RIKEN Omics Science Center, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan. lassmann@gsc.riken.jp.

ABSTRACT
MicroRNAs are small non-coding RNAs that inhibit the translation of target mRNAs. In humans, most microRNAs are transcribed by RNA polymerase II as long primary transcripts and processed by sequential cleavage of the two RNase III enzymes, DROSHA and DICER, into precursor and mature microRNAs, respectively. Although the fundamental functions of microRNAs in RNA silencing have been gradually uncovered, less is known about the regulatory mechanisms of microRNA expression. Here, we report that telomerase reverse transcriptase (TERT) extensively affects the expression levels of mature microRNAs. Deep sequencing-based screens of short RNA populations revealed that the suppression of TERT resulted in the downregulation of microRNAs expressed in THP-1 cells and HeLa cells. Primary and precursor microRNA levels were also reduced under the suppression of TERT. Similar results were obtained with the suppression of either BRG1 (also called SMARCA4) or nucleostemin, which are proteins interacting with TERT and functioning beyond telomeres. These results suggest that TERT regulates microRNAs at the very early phases in their biogenesis, presumably through non-telomerase mechanism(s).

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Related in: MedlinePlus

Comparable effects of TERT, BRG1 and NS in miRNA expression. The expression levels of mature miRNAs and miRNA precursors were examined with RT-qPCR upon suppression of TERT (top), BRG1 (middle) or NS (bottom) by gene-specific shRNAs. For miRNA precursors, there are the primers amplified primary form (†) or both primary and precursor forms (‡). The relative amount of the individual miRNAs was normalized to U6, and the mean expression levels in sh-GFP refer to one. Values represent the means ± SD for three independent experiments. Asterisks represent p < 0.05 compared with sh-GFP.
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ijms-16-01192-f003: Comparable effects of TERT, BRG1 and NS in miRNA expression. The expression levels of mature miRNAs and miRNA precursors were examined with RT-qPCR upon suppression of TERT (top), BRG1 (middle) or NS (bottom) by gene-specific shRNAs. For miRNA precursors, there are the primers amplified primary form (†) or both primary and precursor forms (‡). The relative amount of the individual miRNAs was normalized to U6, and the mean expression levels in sh-GFP refer to one. Values represent the means ± SD for three independent experiments. Asterisks represent p < 0.05 compared with sh-GFP.

Mentions: Recently, we and others have found that TERT interacts with BRG1 and NS and forms the complexes that regulate gene transcription and stem cell functions in both normal and malignant cells [21,25]. We have also found that the TERT/BRG1/NS (TBN) complex exerts an RdRP activity, and it is involved in heterochromatin maintenance [20]. To investigate whether the TBN complex contributes to the miRNA regulation, we conducted RT-qPCR of mature miRNAs and the precursors under the suppression of TERT, BRG1 or NS with gene-specific shRNAs [20,21]. The expression levels of mature miRNAs were reduced to comparable levels when knocking down TERT, BRG1 or NS (Figure 3). The primary and precursor miRNAs were also reduced by either BRG1 or NS suppression, just as seen under TERT suppression. These results support the hypothesis that TERT regulates miRNA transcription together with BRG1 and NS.


Telomerase reverse transcriptase regulates microRNAs.

Lassmann T, Maida Y, Tomaru Y, Yasukawa M, Ando Y, Kojima M, Kasim V, Simon C, Daub CO, Carninci P, Hayashizaki Y, Masutomi K - Int J Mol Sci (2015)

Comparable effects of TERT, BRG1 and NS in miRNA expression. The expression levels of mature miRNAs and miRNA precursors were examined with RT-qPCR upon suppression of TERT (top), BRG1 (middle) or NS (bottom) by gene-specific shRNAs. For miRNA precursors, there are the primers amplified primary form (†) or both primary and precursor forms (‡). The relative amount of the individual miRNAs was normalized to U6, and the mean expression levels in sh-GFP refer to one. Values represent the means ± SD for three independent experiments. Asterisks represent p < 0.05 compared with sh-GFP.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4307298&req=5

ijms-16-01192-f003: Comparable effects of TERT, BRG1 and NS in miRNA expression. The expression levels of mature miRNAs and miRNA precursors were examined with RT-qPCR upon suppression of TERT (top), BRG1 (middle) or NS (bottom) by gene-specific shRNAs. For miRNA precursors, there are the primers amplified primary form (†) or both primary and precursor forms (‡). The relative amount of the individual miRNAs was normalized to U6, and the mean expression levels in sh-GFP refer to one. Values represent the means ± SD for three independent experiments. Asterisks represent p < 0.05 compared with sh-GFP.
Mentions: Recently, we and others have found that TERT interacts with BRG1 and NS and forms the complexes that regulate gene transcription and stem cell functions in both normal and malignant cells [21,25]. We have also found that the TERT/BRG1/NS (TBN) complex exerts an RdRP activity, and it is involved in heterochromatin maintenance [20]. To investigate whether the TBN complex contributes to the miRNA regulation, we conducted RT-qPCR of mature miRNAs and the precursors under the suppression of TERT, BRG1 or NS with gene-specific shRNAs [20,21]. The expression levels of mature miRNAs were reduced to comparable levels when knocking down TERT, BRG1 or NS (Figure 3). The primary and precursor miRNAs were also reduced by either BRG1 or NS suppression, just as seen under TERT suppression. These results support the hypothesis that TERT regulates miRNA transcription together with BRG1 and NS.

Bottom Line: In humans, most microRNAs are transcribed by RNA polymerase II as long primary transcripts and processed by sequential cleavage of the two RNase III enzymes, DROSHA and DICER, into precursor and mature microRNAs, respectively.Although the fundamental functions of microRNAs in RNA silencing have been gradually uncovered, less is known about the regulatory mechanisms of microRNA expression.These results suggest that TERT regulates microRNAs at the very early phases in their biogenesis, presumably through non-telomerase mechanism(s).

View Article: PubMed Central - PubMed

Affiliation: RIKEN Omics Science Center, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan. lassmann@gsc.riken.jp.

ABSTRACT
MicroRNAs are small non-coding RNAs that inhibit the translation of target mRNAs. In humans, most microRNAs are transcribed by RNA polymerase II as long primary transcripts and processed by sequential cleavage of the two RNase III enzymes, DROSHA and DICER, into precursor and mature microRNAs, respectively. Although the fundamental functions of microRNAs in RNA silencing have been gradually uncovered, less is known about the regulatory mechanisms of microRNA expression. Here, we report that telomerase reverse transcriptase (TERT) extensively affects the expression levels of mature microRNAs. Deep sequencing-based screens of short RNA populations revealed that the suppression of TERT resulted in the downregulation of microRNAs expressed in THP-1 cells and HeLa cells. Primary and precursor microRNA levels were also reduced under the suppression of TERT. Similar results were obtained with the suppression of either BRG1 (also called SMARCA4) or nucleostemin, which are proteins interacting with TERT and functioning beyond telomeres. These results suggest that TERT regulates microRNAs at the very early phases in their biogenesis, presumably through non-telomerase mechanism(s).

Show MeSH
Related in: MedlinePlus