Abstract:Gene expression can be regulated by transcriptional or post-transcriptional gene silencing. Recently, we described nuclear nascent RNA silencing that is mediated by Dicer-dependent tRNA-derived small RNA molecules. In addition to tRNA, RNA polymerase III also transcribes vault RNA, a component of the ribonucleoprotein complex vault. Here, we show that Dicer-dependent small vault RNA1-2 (svtRNA1-2) associates with Argonaute 2 (Ago2). Although endogenous vtRNA1-2 is present mostly in the cytoplasm, svtRNA1-2 loc… Show more
“…The AsiSI-ER-U2OS cells at 70% confluency were incubated with 400nM 4-OHT for 4h. Then, the chromatin RNA samples for sequencing were prepared according to previous publications 31,43 . RNA was extracted from the chromatin samples using TRIzol LS (Invitrogen # 10296028)…”
DNA integrity is constantly challenged by both endogenous and exogenous damaging agents, resulting in various forms of damage. Failure to repair DNA accurately leads to genomic instability, a hallmark of cancer. Distinct pathways exist to repair different types of DNA damage. Double-strand breaks (DSBs) represent particularly severe form of damage, due to the physical separation of DNA strands. The repair of DSBs requires the activity of RNA Polymerase II (RNAPII) and the generation of Damage-associated transcripts (DARTs). Here we show that the RNA m5C-methyltransferase NSUN2 localizes to DSBs in a transcription-dependent manner, where it binds to and methylates DARTs. The depletion of NSUN2 results in an accumulation of nascent primary DARTs around DSBs. Furthermore, we detected an RNA-dependent interaction between NSUN2 and DICER, which was stimulated by DNA damage. NSUN2 activity promoted DICER cleavage of DARTs-associated R-loops, which is required for efficient DNA repair. We report a previously unrecognized role of the RNA m5C-methyltransferase NSUN2 within the RNA-dependent DNA damage response, highlighting its function as a DICER chaperone for the clearance of non-canonical substrates such as DARTs, thereby contributing to genomic integrity.
“…The AsiSI-ER-U2OS cells at 70% confluency were incubated with 400nM 4-OHT for 4h. Then, the chromatin RNA samples for sequencing were prepared according to previous publications 31,43 . RNA was extracted from the chromatin samples using TRIzol LS (Invitrogen # 10296028)…”
DNA integrity is constantly challenged by both endogenous and exogenous damaging agents, resulting in various forms of damage. Failure to repair DNA accurately leads to genomic instability, a hallmark of cancer. Distinct pathways exist to repair different types of DNA damage. Double-strand breaks (DSBs) represent particularly severe form of damage, due to the physical separation of DNA strands. The repair of DSBs requires the activity of RNA Polymerase II (RNAPII) and the generation of Damage-associated transcripts (DARTs). Here we show that the RNA m5C-methyltransferase NSUN2 localizes to DSBs in a transcription-dependent manner, where it binds to and methylates DARTs. The depletion of NSUN2 results in an accumulation of nascent primary DARTs around DSBs. Furthermore, we detected an RNA-dependent interaction between NSUN2 and DICER, which was stimulated by DNA damage. NSUN2 activity promoted DICER cleavage of DARTs-associated R-loops, which is required for efficient DNA repair. We report a previously unrecognized role of the RNA m5C-methyltransferase NSUN2 within the RNA-dependent DNA damage response, highlighting its function as a DICER chaperone for the clearance of non-canonical substrates such as DARTs, thereby contributing to genomic integrity.
“…The VAULT-1 locus houses three genes: vtRNA 1-1, vtRNA 1-2, and vtRNA 1-3 [ 55 , 64 ]. Additionally, the VAULT-2 locus encodes vtRNA 2-1, which is also known as pre-miR-886 [ 64 , 65 ]. The biogenesis of vtRNAs is poorly understood (Fig.…”
Section: Vault Rna Biogenesismentioning
confidence: 99%
“…In particular, the integration of the small fragment derived from vtRNA1-2, which was designated svtRNA1-2, was observed. After being incorporated into AGO2, svtRNA1-2 plays a regulatory role, influencing the expression of genes associated with cell adhesion and cell membrane physiology [ 65 ]. Fig.…”
Section: Vault Rna Biogenesismentioning
confidence: 99%
“…This methylation facilitates the fragmentation into small vault RNAs (svtRNAs) by DICER. Some svtRNAs can be loaded into AGO2, regulating posttranscriptional gene silencing [ 65 , 73 ] …”
Section: Vault Rna Biogenesismentioning
confidence: 99%
“…It has been reported that vtRNA1-1 may not undergo cleavage by DICER [ 65 , 66 ]. However, vtRNA1-1 may still serve as a specific substrate for this nuclease [ 67 ].…”
Purpose
Vault (vt) RNAs are noncoding (nc) RNAs transcribed by RNA polymerase III (RNA Pol III) with 5ʹ-triphosphate (5ʹ-PPP) termini that play significant roles and are recognized by innate immune sensors, including retinoic acid-inducible protein 1 (RIG-I). In addition, vtRNAs adopt secondary structures that can be targets of interferon-inducible protein kinase R (PKR) and the oligoadenylate synthetase (OAS)/RNase L system, both of which are important for activating antiviral defenses. However, changes in the expression of vtRNAs have been associated with pathological processes that activate proinflammatory pathways, which influence cellular events such as differentiation, aging, autophagy, apoptosis, and drug resistance in cancer cells.
Results
In this review, we summarized the biology of vtRNAs and focused on their interactions with the innate immune system. These findings provide insights into the diverse roles of vtRNAs and their correlation with various cellular processes to improve our understanding of their biological functions.
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