Prediction and verification of miRNA expression in human and rat retinas.
OBJECTIVE
MicroRNAs (miRNAs) play a global role in regulating gene expression and have important tissue-specific functions. Little is known about their role in the retina. The purpose of this study was to establish the retinal expression of those miRNAs predicted to target genes involved in vision.


METHODS
miRNAs potentially targeting important "retinal" genes, as defined by expression pattern and implication in disease, were predicted using a published algorithm (TargetScan; Envisioneering Medical Technologies, St. Louis, MO). The presence of candidate miRNAs in human and rat retinal RNA was assessed by RT-PCR. cDNA levels for each miRNA were determined by quantitative PCR. The ability to discriminate between miRNAs varying by a single nucleotide was assessed. The activity of miR-124 and miR-29 against predicted target sites in Rdh10 and Impdh1 was tested by cotransfection of miRNA mimics and luciferase reporter plasmids.


RESULTS
Sixty-seven miRNAs were predicted to target one or more of the 320 retinal genes listed herein. All 11 candidate miRNAs tested were expressed in the retina, including miR-7, miR-124, miR135a, and miR135b. Relative levels of individual miRNAs were similar between rats and humans. The Rdh10 3'UTR, which contains a predicted miR-124 target site, mediated the inhibition of luciferase activity by miR-124 mimics in cell culture.


CONCLUSIONS
Many miRNAs likely to regulate genes important for retinal function are present in the retina. Conservation of miRNA retinal expression patterns from rats to humans supports evidence from other tissues that disruption of miRNAs is a likely cause of a range of visual abnormalities.
Arora
Amit
A
Queen's University Belfast, Ophthalmic Research Centre, Institute of Clinical Science, Royal Victoria Hospital, Belfast, United Kingdom.
McKay
Gareth J
GJ
Simpson
David A C
DA
D020413:3' Untranslated Regions / Q000235:genetics; D000429:Alcohol Oxidoreductases / Q000235:genetics*; D000818:Animals; D018929:Cell Culture Techniques; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D007168:IMP Dehydrogenase / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D010957:Plasmids; D051381:Rats; D012160:Retina / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D020413:3' Untranslated Regions; D035683:MicroRNAs; D000429:Alcohol Oxidoreductases; C113992:trans-retinol dehydrogenase; D007168:IMP Dehydrogenase; C488211:IMPDH1 protein, human