Table 1.
Overview of various ncRNAs
| Class | Full Name | Size | Function |
|---|---|---|---|
| Small ncRNAs | |||
| siRNAs | small/short interfering RNAs | 20–21nt | mRNA degradation |
| miRNAs | microRNAs | 18–24nt | post-transcriptional silencing of proteincoding genes and ncRNAs |
| piRNAs | piwi-interacting RNAs | 26–31nt | silencing of mRNAs and transposons |
| rasiRNAs | repeat-associated siRNAs | 24–29nt | transposon silencing |
| crasiRNAs | centromere repeat associated short interacting RNAs | 34–42nt | heterochromatin recruitment |
| tel-sRNAs | telomere small RNAs | 23–28nt | telomere maintenance |
| snoRNAs | small nucleolar RNAs | 60–300nt | rRNA methylation, pseudouridylation, and pre-mRNA processing |
| snRNAs | small nuclear RNAs | <200nt | pre-mRNA splicing |
| PASRs | promoter-associated short RNAs | 20–200nt | transcriptional regulation of gene expression |
| tiRNAs | transcription initiation RNAs | 18nt | transcriptional regulation of gene expression |
| TSSa-RNAs | transcription start site-associated RNAs | 20–90nt | transcriptional regulation of gene expression |
| PROMPTs | promoter upstream transcripts | 18nt | transcriptional regulation of gene expression |
| spliRNAs | splice junction-associated RNAs | 17–18nt | epigenetic regulation of gene expression |
| TASRs | termini-associated short RNAs | 20–200nt | pervasive transcription |
| CRISP | clustered regularly interspaced short palindromic repeats | 24–48nt | prokaryotic immune control |
| tasiRNAs | trans-acting siRNAs | 20–22nt | gene silencing in plants |
| vRNAs | vault RNAs | 88–98nt | multidrug resistance, apoptosis resistance and innate immunity |
| mito-sncRNAs | mitochondrial small non-coding RNAs | <200nt | regulation of mitochondrial gene expression |
| MSY-RNAs | MSY2-associated RNAs | 26–30nt | unknown |
| moRNAs | microRNA-offset RNAs | ~20 nt | unknown |
| tRNA-derived RNAs | tRNA-derived RNAs | 19–40nt | Inhibition of mRNA translation |
| sdRNAs | sno-derived RNAs | <50nt | miRNA-like regulators of translation |
| xiRNAs | X-inactivation RNAs | <50nt | X-chromosome inactivation |
| Y RNAs | Y RNAs | ~100nt | DNA replication |
| Long ncRNAs | |||
| LincRNAs | long intergenic non-coding RNAs | >200nt | epigenetic regulation and chromatin remodeling; transcriptional control |
| eRNAs | enhancer RNAs | >200nt | promoting mRNA synthesis |
| uaRNAs | 3′ untranslated region (UTR)-derived RNAs | >200nt | regulation of mRNA stability, translation, and localization |
| NATs | natural antisense transcripts | >200nt | chromatin modifications; regulation of transcription, mRNA stability, splicing, and translation |
| TERRA | telomeric repeat-containing RNAs | >200nt | maintenance of telomere integrity |
| T-UCR/E | transcribed ultraconserved region/element | >200 nt | splicing and epigenetic modifications, transcriptional coactivator |
| PALRs | promoter-associated long RNAs | >200 nt | transcriptional regulation of gene expression |
| SUT | stable unannotated transcript | >200 nt | transposon silencing |
| CUT | cryptic unstable transcript | >200 nt | gene regulation and silencing |
| mito-lncRNAs | mitochondrial long non-coding RNA | >200 nt | regulation of mitochondrial gene expression |
| Pseudogenes | pseudogenes | >200 nt | modulators of gene expression |