Mir-1 microRNA precursor family

miR-1
mIR-1 microRNA precursor family
Identifiers
Symbol	mir-1
Rfam	RF00103
miRBase	MI0000651
miRBase family	MIPF0000038
Entrez	406904
HUGO	HGNC:31499
OMIM	609326
Other data
RNA type	Gene; miRNA;
Domain(s)	Metazoa
GO	0035195
SO	0001244
Locus	Chr. 20 q13.33

The miR-1 microRNA precursor is a small micro RNA that regulates its target protein's expression in the cell. microRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~22 nucleotide products. In this case the mature sequence comes from the 3' arm of the precursor. The mature products are thought to have regulatory roles through complementarity to mRNA. In humans there are two distinct microRNAs that share an identical mature sequence, these are called miR-1-1 and miR-1-2.

These micro RNAs have pivotal roles in development and physiology of muscle tissues including the heart. MiR-1 is known to be involved in important role in heart diseases such as hypertrophy, myocardial infarction, and arrhythmias. Studies have shown that MiR-1 is an important regulator of heart adaption after ischemia or ischaemic stress and it is upregulated in the remote myocardium of patients with myocardial infarction. Also MiR-1 is downregulated in myocardial infarcted tissue compared to healthy heart tissue. Plasma levels of MiR-1 can be used as a sensitive biomarker for myocardial infarction.

The heat shock protein, HSP60 is also known to be a target for post-transcriptional regulation by miR-1 and miR-206. HSP60 is a component of the defence mechanism against diabetic myocardial injury and its level is reduced in the diabetic myocardium. In both in vivo and in vitro experiments increased levels of glucose in myocardiomyctes led to significant upregulation of miR-1 and miR-206 with resulting modulation of HSP60 leading to accelerated glucose-mediated apoptosis in cardiomyocetes. The level of HSP70 is also a target for post-transcriptional repression by MiR-1.

MiR-1 has key roles in the development and differentiation of smooth and skeletal muscles. For example, in the lineage-specific differention of smooth muscle cells from embroyonic stem cell derived cultures, MiR-1 is required; as its loss of function resulted in a reduction in smooth muscle cell biomarkers and a reduction in the derived smooth muscle cell population. There is evidence that the control of smooth muscle cell differentiation by MiR-1 may be mediated by the down regulation of Kruppel-like factor 4 (KLF4), since a MiR-1 recognition site is predicted in the 3' UTR of KLF4 and inhibition of MiR-1 results in reversed down-regulation of KLF4 and an inhibition of smooth muscle cell differentiation. A mutation in the 3' UTR of the myostatin gene in Texel sheep creates a miR-1 and miR-206 target site. This is likely to cause the muscular phenotype of this breed of sheep.