title: Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor X (RFX) transcription factors through X-box promoter motifs.
abstract: DYX1C1, DCDC2, and KIAA0319 are three of the most replicated dyslexia candidate genes (DCGs). Recently, these DCGs were implicated in functions at the cilium. Here, we investigate the regulation of these DCGs by Regulatory Factor X transcription factors (RFX TFs), a gene family known for transcriptionally regulating ciliary genes. We identify conserved X-box motifs in the promoter regions of DYX1C1, DCDC2, and KIAA0319 and demonstrate their functionality, as well as the ability to recruit RFX TFs using reporter gene and electrophoretic mobility shift assays. Furthermore, we uncover a complex regulation pattern between RFX1, RFX2, and RFX3 and their significant effect on modifying the endogenous expression of DYX1C1 and DCDC2 in a human retinal pigmented epithelial cell line immortalized with hTERT (hTERT-RPE1). In addition, induction of ciliogenesis increases the expression of RFX TFs and DCGs. At the protein level, we show that endogenous DYX1C1 localizes to the base of the cilium, whereas DCDC2 localizes along the entire axoneme of the cilium, thereby validating earlier localization studies using overexpression models. Our results corroborate the emerging role of DCGs in ciliary function and characterize functional noncoding elements, X-box promoter motifs, in DCG promoter regions, which thus can be targeted for mutation screening in dyslexia and ciliopathies associated with these genes.-Tammimies, K., Bieder, A., Lauter, G., Sugiaman-Trapman, D., Torchet, R., Hokkanen, M.-E., Burghoorn, J., Castrén, E., Kere, J., Tapia-Páez, I., Swoboda, P. Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor (RF) X transcription factors through X-box promoter motifs.
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden; Center of Neurodevelopmental Disorders (KIND), Pediatric Neuropsychiatry Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Tammimies
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bieder
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Lauter
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Debora
authors.initials: D
authors.lastname: Sugiaman-Trapman
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Rachel
authors.initials: R
authors.lastname: Torchet
authors.affiliation: Neuroscience Center, University of Helsinki, Helsinki, Finland.
authors.forename: Marie-Estelle
authors.initials: ME
authors.lastname: Hokkanen
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Burghoorn
authors.affiliation: Neuroscience Center, University of Helsinki, Helsinki, Finland.
authors.forename: Eero
authors.initials: E
authors.lastname: Castrén
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden; Molecular Neurology Research Program, University of Helsinki, Helsinki, Finland; and Folkhälsan Institute of Genetics, Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Kere
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden; isabel.tapia@ki.se.
authors.forename: Isabel
authors.initials: I
authors.lastname: Tapia-Páez
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden; peter.swoboda@ki.se.
authors.forename: Peter
authors.initials: P
authors.lastname: Swoboda
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D017173:Caenorhabditis elegans; D002478:Cells, Cultured; D002923:Cilia / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004410:Dyslexia / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D000071701:Regulatory Factor X Transcription Factors / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; C510451:DCDC2 protein, human; C478878:DNAAF4 protein, human; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D000071701:Regulatory Factor X Transcription Factors
keywords: ciliary proteins; ciliopathies; gene regulation; hTERT-RPE1 cell line; reading disorder