The vertebrate-specific transcription factor RE-1 silencing transcription factor or neuron-restrictive silencer factor (REST/NRSF) was first described as a negative regulator restricting expression of neuronal genes to neurons in a variety of genetic contexts. However, REST/NRSF has a more general role in the regulation of gene expression that involves chromatin remodelling via a SWI/SNF complex. We identified a 677 gene repertoire of potential REST/NRSF-dependent genes taking advantage of Rest/Nrsf gene silencing in a mouse cell line. Using Ka/Ks analysis, we found that REST/NRSF protein, REST/NRSF interactors and the products of REST/NRSF-dependent genes display significantly higher rates of protein evolution in primates than in rodents. The McDonald-Kreitman test indicated positive selection for human REST/NRSF and nuclear RNA-binding proteins encoded by REST/NRSFdependent genes. In these proteins, we demonstrated sites under positive selection within the primate’s clade. Importantly, the REST/NRSF-dependent gene repertoire is statistically enriched in genes disrupted in neuropsychiatric diseases such as schizophrenia. In addition, we found that Smarca2 (Brm), Smarcd3 (Baf60c), Smarce1 (Baf57), Hdac1, RcoR1, and Mecp2, which are part of the REST/NRSFSWI/SNF chromatin remodelling complex, are transcriptionally regulated by REST/NRSF. Changing their gene dosage in vitro induced abnormal dendritic and dendritic spine phenotypes that were previously observed in rodent models of neuropsychiatric diseases. Altogether, these results suggest that genes encoding proteins of the REST/NRSF-SWI/SNF pathway display primate-specific accelerated
evolution. It may be hypothesized that the subset of genes involved in this pathway, which display a primate evolutionary signature in specific sites, may represent a novel gene candidate repertoire for neuropsychiatric diseases.
Overall design: Agilent Whole Mouse Genome oligomicroarrays (GEO accession no. GPL2872, Agilent Technologies, Palo Alto, CA) were used. They contain 60-mer DNA probes synthesized in situ in a 44k format. Of 44,290 spots, 2756 are controls. The remaining 41,534 spots represent 33,661 unique transcripts which correspond to 20,202 unique human genes. Six independent (NRSF silencing overexpression, six individual samples) measurements were carried out for each group of biological conditions using exchanged dye-labeled RNA targets (i.e., Cy3 and Cy5 dyeswapping experiments).
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