Evidence for natural antisense transcript-mediated inhibition of microRNA function.
BACKGROUND
MicroRNAs (miRNAs) have the potential to regulate diverse sets of mRNA targets. In addition, mammalian genomes contain numerous natural antisense transcripts, most of which appear to be non-protein-coding RNAs (ncRNAs). We have recently identified and characterized a highly conserved non-coding antisense transcript for beta-secretase-1 (BACE1), a critical enzyme in Alzheimer's disease pathophysiology. The BACE1-antisense transcript is markedly up-regulated in brain samples from Alzheimer's disease patients and promotes the stability of the (sense) BACE1 transcript.


RESULTS
We report here that BACE1-antisense prevents miRNA-induced repression of BACE1 mRNA by masking the binding site for miR-485-5p. Indeed, miR-485-5p and BACE1-antisense compete for binding within the same region in the open reading frame of the BACE1 mRNA. We observed opposing effects of BACE1-antisense and miR-485-5p on BACE1 protein in vitro and showed that Locked Nucleic Acid-antimiR mediated knockdown of miR-485-5p as well as BACE1-antisense over-expression can prevent the miRNA-induced BACE1 suppression. We found that the expression of BACE1-antisense as well as miR-485-5p are dysregulated in RNA samples from Alzheimer's disease subjects compared to control individuals.


CONCLUSIONS
Our data demonstrate an interface between two distinct groups of regulatory RNAs in the computation of BACE1 gene expression. Moreover, bioinformatics analyses revealed a theoretical basis for many other potential interactions between natural antisense transcripts and miRNAs at the binding sites of the latter.
Faghihi
Mohammad Ali
MA
Department of Neuroscience, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA. mohfag@scripps.edu
Zhang
Ming
M
Huang
Jia
J
Modarresi
Farzaneh
F
Van der Brug
Marcel P
MP
Nalls
Michael A
MA
Cookson
Mark R
MR
St-Laurent
Georges
G
Wahlestedt
Claes
C
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology / Q000235:genetics; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D002460:Cell Line; D057166:High-Throughput Screening Assays; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000494:pharmacology; D016366:Open Reading Frames / Q000235:genetics; D016372:RNA, Antisense / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA
D035683:MicroRNAs; D009841:Oligonucleotides; D016372:RNA, Antisense; D012333:RNA, Messenger; D022661:RNA, Untranslated; C477371:locked nucleic acid; D008156:Luciferases; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse