RasiRNA in the context of "Argonaute"

RNA silencing or RNA interference refers to a family of gene silencing effects by which gene expression is negatively regulated by non-coding RNAs such as microRNAs. RNA silencing may also be defined as sequence-specific regulation of gene expression triggered by double-stranded RNA (dsRNA). RNA silencing mechanisms are conserved among most eukaryotes. The most common and well-studied example is RNA interference (RNAi), in which endogenously expressed microRNA (miRNA) or exogenously derived small interfering RNA (siRNA) induces the degradation of complementary messenger RNA. Other classes of small RNA have been identified, including piwi-interacting RNA (piRNA) and its subspecies repeat associated small interfering RNA (rasiRNA).

Small RNA (sRNA) are polymeric RNA molecules that are less than 200 nucleotides in length, and are usually non-coding. RNA silencing is often a function of these molecules, with the most common and well-studied example being RNA interference (RNAi), in which endogenously (from within the organism) expressed microRNA (miRNA) or endogenously/exogenously (from outside the organism) derived small interfering RNA (siRNA) induces the degradation of complementary messenger RNA. Other classes of small RNA have been identified, including piwi-interacting RNA (piRNA) and its subspecies repeat associated small interfering RNA (rasiRNA). Small RNA "is unable to induce RNAi alone, and to accomplish the task it must form the core of the RNA–protein complex termed the RNA-induced silencing complex (RISC), specifically with Argonaute protein".

Small RNA have been detected or sequenced using a range of techniques, including directly by MicroRNA sequencing on several sequencing platforms, or indirectly through genome sequencing and analysis. Identification of miRNAs has been evaluated in detecting human disease, such as breast cancer. Peripheral blood mononuclear cell (PBMC) miRNA expression has been studied as potential biomarker for different neurological disorders such as Parkinson's disease, Multiple sclerosis. Evaluating small RNA is useful for certain kinds of study because its molecules "do not need to be fragmented prior to library preparation".