How do microRNAs miRNAs influence the expression of a gene?
miRNAs (microRNAs) are short non-coding RNAs that regulate gene expression post-transcriptionally. They generally bind to the 3′-UTR (untranslated region) of their target mRNAs and repress protein production by destabilizing the mRNA and translational silencing.
Are miRNAs expressed?
Intergenic miRNAs have their own promoters, are expressed independently and can be regulated by separate transcription factors. In both cases, the expression of microRNA can change due to different mutations or can be regulated by methylation of the promoter.
How are microRNA expressed?
Instead of being cleaved by two different enzymes, once inside and once outside the nucleus, both cleavages of the plant miRNA are performed by a Dicer homolog, called Dicer-like1 (DL1). DL1 is expressed only in the nucleus of plant cells, which indicates that both reactions take place inside the nucleus.
What is the function of miRNAs?
The miRNA functions as a guide by base-pairing with target mRNA to negatively regulate its expression. The level of complementarity between the guide and mRNA target determines which silencing mechanism will be employed; cleavage of target messenger RNA (mRNA) with subsequent degradation or translation inhibition Fig.
How are miRNAs regulated?
Where do miRNAs bind to?
Mechanisms of miRNA-Mediated Gene Regulation. Most studies to date have shown that miRNAs bind to a specific sequence at the 3′ UTR of their target mRNAs to induce translational repression and mRNA deadenylation and decapping (40, 41).
How are miRNAs different from other gene products?
miRNA genes were less conserved than other RNA genes, although their mature miRNA sequences were highly conserved. The nucleotides in pre-miRNAs formed more hydrogen bonds and base pairs than in other RNAs. miRNAs had higher negative adjusted minimal folding free energies than other RNAs except tRNAs (p < 0.001).
What regulates MicroRNA expression?
The expression of miRNAs is regulated by multiple factors and molecular mechanisms, from those affecting the DNA copy number, methylation of CpGs, transcription factors, and miRNA biogenesis, to those modifying the miRNA binding site’s availability in the mRNA sequence.
