regulatory ncRNA-mediated post-transcriptional gene silencing

Definition

Target type: biologicalprocess

A posttranscriptional gene silencing pathway in which regulatory RNAs elicit silencing of specific target genes, either by mRNA destabilization or inhibition of translation. [GOC:ems, PMID:11201747, PMID:11713190, PMID:15020054, PMID:15066275, PMID:18771919, PMID:32885814, PMID:33184244]

Regulatory non-coding RNAs (ncRNAs) play a crucial role in post-transcriptional gene silencing, a complex process that modulates gene expression after transcription. This intricate mechanism involves a diverse repertoire of ncRNAs, including microRNAs (miRNAs), small interfering RNAs (siRNAs), and long non-coding RNAs (lncRNAs), each with unique modes of action.

miRNAs, typically 20-25 nucleotides long, are key players in post-transcriptional silencing. They are transcribed as primary transcripts (pri-miRNAs) and processed into mature miRNAs by a series of enzymatic steps. Mature miRNAs associate with the RNA-induced silencing complex (RISC), a multi-protein complex that facilitates target recognition. The miRNA within RISC binds to complementary sequences within the 3' untranslated region (3'UTR) of target mRNAs, leading to translational repression or mRNA degradation.

siRNAs, also approximately 20-25 nucleotides long, arise from double-stranded RNA precursors. These precursors are cleaved by the enzyme Dicer into siRNA duplexes, which are then loaded into RISC. Like miRNAs, siRNAs guide RISC to target mRNAs, triggering mRNA degradation through perfect or near-perfect base pairing.

lncRNAs, longer than 200 nucleotides, exhibit diverse mechanisms of action. Some lncRNAs act as molecular scaffolds, bringing together protein complexes that regulate gene expression. Others function as decoys, sequestering proteins or miRNAs to prevent their interaction with target mRNAs. Additionally, lncRNAs can directly interact with chromatin, influencing the accessibility of genes to transcription factors.

The post-transcriptional silencing mediated by ncRNAs is a highly regulated process. It is influenced by cellular context, developmental stage, and environmental cues. This intricate interplay ensures that gene expression is fine-tuned to meet the specific needs of the cell. Furthermore, dysregulation of ncRNA-mediated silencing is implicated in various diseases, highlighting the importance of this process for human health.'
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Proteins (3)

Compounds (5)