title: Transcriptional and post-transcriptional regulation of SPAST, the gene most frequently mutated in hereditary spastic paraplegia.
abstract: Hereditary spastic paraplegias (HSPs) comprise a group of neurodegenerative disorders that are characterized by progressive spasticity of the lower extremities, due to axonal degeneration in the corticospinal motor tracts. HSPs are genetically heterogeneous and show autosomal dominant inheritance in ∼70-80% of cases, with additional cases being recessive or X-linked. The most common type of HSP is SPG4 with mutations in the SPAST gene, encoding spastin, which occurs in 40% of dominantly inherited cases and in ∼10% of sporadic cases. Both loss-of-function and dominant-negative mutation mechanisms have been described for SPG4, suggesting that precise or stoichiometric levels of spastin are necessary for biological function. Therefore, we hypothesized that regulatory mechanisms controlling expression of SPAST are important determinants of spastin biology, and if altered, could contribute to the development and progression of the disease. To examine the transcriptional and post-transcriptional regulation of SPAST, we used molecular phylogenetic methods to identify conserved sequences for putative transcription factor binding sites and miRNA targeting motifs in the SPAST promoter and 3'-UTR, respectively. By a variety of molecular methods, we demonstrate that SPAST transcription is positively regulated by NRF1 and SOX11. Furthermore, we show that miR-96 and miR-182 negatively regulate SPAST by effects on mRNA stability and protein level. These transcriptional and miRNA regulatory mechanisms provide new functional targets for mutation screening and therapeutic targeting in HSP.
authors.affiliation: Birth Defects Laboratories, Division of Medical Genetics, Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Henson
authors.forename: Wan
authors.initials: W
authors.lastname: Zhu
authors.forename: Kelsey
authors.initials: K
authors.lastname: Hardaway
authors.forename: Jaime L
authors.initials: JL
authors.lastname: Wetzel
authors.forename: Mihaela
authors.initials: M
authors.lastname: Stefan
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Albers
authors.forename: Robert D
authors.initials: RD
authors.lastname: Nicholls
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000251:Adenosine Triphosphatases / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017124:Conserved Sequence / Q000235:genetics; D005786:Gene Expression Regulation; D056426:Genetic Loci / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D059645:Mutation Rate; D051266:Nuclear Respiratory Factor 1 / Q000378:metabolism; D059372:Nucleotide Motifs / Q000235:genetics; D010264:Paraplegia / Q000175:diagnosis / Q000201:enzymology* / Q000235:genetics* / Q000628:therapy; D011323:Primates / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D043484:Proprotein Convertases / Q000378:metabolism; D055751:SOXC Transcription Factors / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D000074181:Spastin; D014158:Transcription, Genetic
chemical_list: D020413:3' Untranslated Regions; C541492:MIRN96 microRNA, human; D035683:MicroRNAs; C538984:Mirn182 microRNA, human; C495633:NRF1 protein, human; D051266:Nuclear Respiratory Factor 1; C097473:SOX11 protein, human; D055751:SOXC Transcription Factors; C080654:PCSK6 protein, human; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; D000251:Adenosine Triphosphatases; D000074181:Spastin; C400283:SPAST protein, human