Labeled microRNA pull-down assay system: an experimental approach for high-throughput identification of microRNA-target mRNAs.
We developed a simple, direct and cost-effective approach to search for the most likely target genes of a known microRNA (miRNA) in vitro. We term this method 'labeled miRNA pull-down (LAMP)' assay system. Briefly, the pre-miRNA is labeled with digoxigenin (DIG), mixed with cell extracts and immunoprecipitated by anti-DIG antiserum. When the DIG-labeled miRNA and bound mRNA complex are obtained, the total cDNAs are then subcloned and sequenced, or RT-PCR-amplified, to search for the putative target genes of a known miRNA. After successfully identifying the known target genes of Caenorhabditis elegans miRNAs lin-4 and let-7 and zebrafish let-7, we applied LAMP to find the unknown target gene of zebrafish miR-1, which resulted in the identification of hand2. We then confirmed hand2 as a novel target gene of miR-1 by whole-mount in situ hybridization and luciferase reporter gene assay. We further validated this target gene by microarray analysis, and the results showed that hand2 is the top-scoring among 302 predicted putative target genes. We concluded that LAMP is an experimental approach for high-throughput identification of the target gene of known miRNAs from both C. elegans and zebrafish, yielding fewer false positive results than those produced by using only the bioinformatics approach.
Hsu
Ren-Jun
RJ
Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan.
Yang
Hsin-Jung
HJ
Tsai
Huai-Jen
HJ
D020413:3' Untranslated Regions / Q000737:chemistry; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D019556:COS Cells; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D047468:Immunoprecipitation / Q000379:methods*; D035683:MicroRNAs / Q000302:isolation & purification / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D012322:RNA Precursors / Q000302:isolation & purification / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
D020413:3' Untranslated Regions; D051792:Basic Helix-Loop-Helix Proteins; D035683:MicroRNAs; D012322:RNA Precursors; D012333:RNA, Messenger; D029961:Zebrafish Proteins; C410915:hand2 protein, zebrafish