SaRNA
Encyclopedia
Small activating RNA molecules can induce target gene expression in a phenomenon referred to as dsRNA-induced transcriptional activation (RNAa
).
Small double-stranded RNA (dsRNA), such as small interfering RNA (siRNA
) and microRNA (miRNA
), have been found to be the trigger of an evolutionary conserved mechanism known as RNA interference
(RNAi). RNAi invariably leads to gene silencing via remodeling chromatin
to thereby suppress transcription, degrading complementary mRNA, or blocking protein translation. Recent discoveries now suggest that dsRNAs may also act as small activating RNAs (saRNA). By targeting sequences in gene promoters, saRNAs readily induce target gene expression in a phenomenon referred to as dsRNA-induced transcriptional activation (RNAa
). This discovery expands our knowledge on both the functionality and complexity small RNAs have in regulating gene expression.
Gene activation by RNAa
appears to be long-lasting. Induction of gene expression has been seen to last for over ten days. The prolonged effect of RNAa could be attributed to epigenetic changes at dsRNA target sites.
RNAa
Small double-stranded RNA has been found to silence gene expression by an evolutionally conserved mechanism known as RNA interference or RNAi. Such dsRNAs are called small interfering RNAs or siRNA. RNAi can occur at both transcriptional and post-transcriptional levels...
).
Small double-stranded RNA (dsRNA), such as small interfering RNA (siRNA
Sírna
Sírna Sáeglach , son of Dian mac Demal, son of Demal mac Rothechtaid, son of Rothechtaid mac Main, was, according to medieval Irish legend and historical tradition, a High King of Ireland...
) and microRNA (miRNA
Mirna
Mirna may refer to:geographical entities* Mirna , a river in Istria, Croatia* Mirna , a river in Slovenia, tributary of the river Sava* Mirna , a settlement in the municipality of Mirna in Southeastern Sloveniapeople...
), have been found to be the trigger of an evolutionary conserved mechanism known as RNA interference
RNA interference
RNA interference is a process within living cells that moderates the activity of their genes. Historically, it was known by other names, including co-suppression, post transcriptional gene silencing , and quelling. Only after these apparently unrelated processes were fully understood did it become...
(RNAi). RNAi invariably leads to gene silencing via remodeling chromatin
Chromatin
Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are; to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene...
to thereby suppress transcription, degrading complementary mRNA, or blocking protein translation. Recent discoveries now suggest that dsRNAs may also act as small activating RNAs (saRNA). By targeting sequences in gene promoters, saRNAs readily induce target gene expression in a phenomenon referred to as dsRNA-induced transcriptional activation (RNAa
RNAa
Small double-stranded RNA has been found to silence gene expression by an evolutionally conserved mechanism known as RNA interference or RNAi. Such dsRNAs are called small interfering RNAs or siRNA. RNAi can occur at both transcriptional and post-transcriptional levels...
). This discovery expands our knowledge on both the functionality and complexity small RNAs have in regulating gene expression.
Gene activation by RNAa
RNAa
Small double-stranded RNA has been found to silence gene expression by an evolutionally conserved mechanism known as RNA interference or RNAi. Such dsRNAs are called small interfering RNAs or siRNA. RNAi can occur at both transcriptional and post-transcriptional levels...
appears to be long-lasting. Induction of gene expression has been seen to last for over ten days. The prolonged effect of RNAa could be attributed to epigenetic changes at dsRNA target sites.
Further reading
- Morris KV (2008). RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity. Caister Academic Press ISBN 978-1-904455-25-7
- Tost J (2008). Epigenetics. Caister Academic Press ISBN 978-1-904455-23-3
External links
- Small RNAs Reveal an Activating Side. Science News of the Week
- How to get your genes switched on. New Scientist 16 November 2006