title: Motor neuron-expressed microRNAs 218 and their enhancers are nested within introns of Slit2/3 genes.
abstract: miR218-1 and miR218-2 are embedded in introns of SLIT2 and SLIT3, respectively, an arrangement conserved throughout vertebrate genomes. Both miR218 genes are predicted to be transcribed in the same orientation as their host genes and were assumed to be spliced from Slit2/3 primary transcripts. In zebrafish miR218 is active in cranial nerve motor nuclei and spinal cord motor neurons, while slit2 and slit3 are expressed predominantly in the midline. This differential expression pattern suggested independent regulation of miR218 genes by distinct enhancers. We tested conserved noncoding elements for regulatory activity by reporter gene transgenesis in zebrafish. Two human enhancers, 76 kb and 130 kb distant from miR218-2, were identified that drove GFP expression in zebrafish in an almost complete miR218 expression pattern. In the zebrafish slit3 locus, two enhancers with identical activity were discovered. In human SLIT2 one enhancer 52 kb upstream of miR218-1 drove an expression pattern very similar to the enhancers of miR218-2. This establishes that miR218-1/-2 regulatory units are nested within SLIT2/3 and that they are duplicates of an ancestral single locus. Due to the strong activity of the enhancers, unique transgenic lines were created that facilitate morphological and gene functional genetic experiments in motor neurons.
authors: Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.
authors: Beena
authors: B
authors: Punnamoottil
authors: Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.|Department of Physiology, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.
authors: Silke
authors: S
authors: Rinkwitz
authors: Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.
authors: Jean
authors: J
authors: Giacomotto
authors: Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.
authors: Adam J
authors: AJ
authors: Svahn
authors: Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.|Department of Physiology, Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia.
authors: Thomas S
authors: TS
authors: Becker
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D007438:Introns; D035683:MicroRNAs / Q000235:genetics*; D009046:Motor Neurons / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism; D000098552:Slit Homolog 2 Protein
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D035683:MicroRNAs; D009419:Nerve Tissue Proteins; C504433:Slit3 protein, zebrafish; D029961:Zebrafish Proteins; D000098552:Slit Homolog 2 Protein
keywords: GRB; conserved synteny; gene duplication; genomic regulatory blocks; long-range gene regulation; microRNA