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Primary micro RNA precursor transcripts are localized at post‐synaptic densities in adult mouse forebrain
Author(s) -
Lugli Giovanni,
Larson John,
Demars Michael P.,
Smalheiser Neil R.
Publication year - 2012
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2012.07921.x
Subject(s) - drosha , rna , microrna , microbiology and biotechnology , biology , messenger rna , small hairpin rna , rna binding protein , forebrain , rna editing , gene , rna interference , biochemistry , neuroscience , central nervous system
In a previous study, we reported that microRNA (mi RNA ) precursors are expressed in synaptic fractions within adult mouse forebrain, where they are enriched at post‐synaptic densities ( PSD s). However, because that study employed qRT‐PCR primers that recognize the hairpin region, it was not able to distinguish between primary micro RNA gene transcripts (pri‐miRs) and small hairpin precursors (pre‐miRs). Here, using primer sets that selectively measure regions upstream, downstream and flanking the hairpin, we demonstrate that pri‐miRs are present in synaptic fractions (enriched several‐fold relative to total tissue homogenate) and are especially enriched in isolated PSD s. Drosha and DGCR 8 proteins are also expressed in synaptic fractions and PSD s, and are tightly associated with pri‐miRs as assessed by coimmunoprecipitation under stringent conditions. Pri‐miRs, drosha, and DGCR 8 are highly enriched in fractions that contain mRNA transport particles, and cytosolic drosha is associated with kinesin heavy chain; these findings suggest that pri‐miRs are transported to synaptic regions in a manner similar to mRNA s. This study supports the notion that mi RNA biogenesis occurs locally near synapses in a regulated fashion.