Mir-155

pre-mir-155
pre-mir-155 secondary structure and sequence conservation.ard
Identifiers
Symbol	miR-155
Rfam	RF00731
miRBase family	MIPF0000157
Other data
RNA type	microRNA
Domain(s)	Eukaryota;
SO	{{{SO}}}

406947

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ENSG00000283904

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MiR-155 is a microRNA that in humans is encoded by the MIR155 host gene or MIR155HG. MiR-155 plays a role in various physiological and pathological processes.Exogenous molecular control in vivo of miR-155 expression may inhibit malignant growth,viral infections, and enhance the progression of cardiovascular diseases.

The MIR155HG was initially identified as a gene that was transcriptionally activated by promoter insertion at a common retroviral integration site in B-cell lymphomas and was formerly called BIC (B-cell Integration Cluster). It was demonstrated that miR-155 over-expression supports the development and aggresivness of B cell malignancies. The MIR155HG is transcribed by RNA polymerase II and the resulting ~1,500 nucleotide RNA is capped and polyadenylated. The 23 nucleotide single-stranded miR-155, which is harbored in exon 3, is subsequently processed from the parent RNA molecule.

The MIR155HG RNA transcript does not contain a long open reading frame (ORF), however, it does include an imperfectly base-paired stem loop that is conserved across species. This non-coding RNA (ncRNA) is now defined as a primary-miRNA (pri-miRNA). Once miR-155 pri-miRNA is transcribed, this transcript is cleaved by the nuclear microprocessor complex, of which the core components are the RNase III type endonuclease Drosha and the DiGeorge critical region 8 (DGCR8) protein, to produce a 65 nucleotide stem-loop precursor miRNA (pre-mir-155) (see Figure 2).