Biomaterial Database

An extended inhibitory context causes skipping of exon 7 of SMN2 in spinal muscular atrophy. 2004

Natalia N Singh, and Elliot J Androphy, and Ravindra N Singh

Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605-2324, USA.

SMN1 and SMN2 represent the two nearly identical copies of the survival of motor neuron gene in humans. The most frequent cause of spinal muscular atrophy (SMA) is loss of SMN1 accompanied by the inability of SMN2 to compensate due to an inhibitory mutation at position 6 in exon 7 (C6U) that causes exon 7 exclusion. How this single exonic nucleotide regulates exon 7 recognition has been of major interest. Based on score matrices and in vitro assays, abrogation of an exonic splicing enhancer (ESE) associated with SF2/ASF has been considered as the cause of exon 7 exclusion. However, a recent report supports the creation of an exonic splicing silencer (ESS) associated with hnRNP A1 as the determining factor for exon 7 exclusion. Here we show that C6U strengthens an inhibitory context that covers a larger sequence than the hnRNP A1 binding site. The inhibitory context can also be strengthened by the addition of a G residue at the first position of exon 7 in SMN1, promoting exon 7 skipping despite the presence of SF2/ASF binding site. Through in vivo selection and a series of mutations we demonstrate that the strengthening of the extended inhibitory context at the 5' end of exon 7 is exercised through overlapping sequence motifs that collaborate to regulate exon usage.

UI	MeSH Term	Description	Entries
D008957	Models, Genetic	Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Genetic Models,Genetic Model,Model, Genetic
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009134	Muscular Atrophy, Spinal	A group of disorders marked by progressive degeneration of motor neurons in the spinal cord resulting in weakness and muscular atrophy, usually without evidence of injury to the corticospinal tracts. Diseases in this category include Werdnig-Hoffmann disease and later onset SPINAL MUSCULAR ATROPHIES OF CHILDHOOD, most of which are hereditary. (Adams et al., Principles of Neurology, 6th ed, p1089)	Bulbospinal Neuronopathy,Oculopharyngeal Spinal Muscular Atrophy,Progressive Muscular Atrophy,Scapuloperoneal Form of Spinal Muscular Atrophy,Spinal Muscular Atrophy,Adult Spinal Muscular Atrophy,Adult-Onset Spinal Muscular Atrophy,Amyotrophy, Neurogenic Scapuloperoneal, New England Type,Distal Spinal Muscular Atrophy,Hereditary Motor Neuronopathy,Muscular Atrophy, Adult Spinal,Myelopathic Muscular Atrophy,Myelopathic Muscular Atrophy, Progressive,Progressive Myelopathic Muscular Atrophy,Progressive Proximal Myelopathic Muscular Atrophy,Proximal Myelopathic Muscular Atrophy, Progressive,Scapuloperoneal Spinal Muscular Atrophy,Spinal Amyotrophy,Spinal Muscular Atrophy, Distal,Spinal Muscular Atrophy, Oculopharyngeal,Spinal Muscular Atrophy, Scapuloperoneal,Spinal Muscular Atrophy, Scapuloperoneal Form,Adult Onset Spinal Muscular Atrophy,Amyotrophies, Spinal,Amyotrophy, Spinal,Atrophies, Progressive Muscular,Atrophy, Myelopathic Muscular,Atrophy, Progressive Muscular,Atrophy, Spinal Muscular,Bulbospinal Neuronopathies,Hereditary Motor Neuronopathies,Motor Neuronopathies, Hereditary,Motor Neuronopathy, Hereditary,Muscular Atrophies, Progressive,Muscular Atrophy, Myelopathic,Muscular Atrophy, Progressive,Neuronopathies, Bulbospinal,Neuronopathies, Hereditary Motor,Neuronopathy, Bulbospinal,Neuronopathy, Hereditary Motor,Progressive Muscular Atrophies,Spinal Amyotrophies
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009419	Nerve Tissue Proteins		Proteins, Nerve Tissue,Tissue Proteins, Nerve
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D004742	Enhancer Elements, Genetic	Cis-acting DNA sequences which can increase transcription of genes. Enhancers can usually function in either orientation and at various distances from a promoter.	Enhancer Elements,Enhancer Sequences,Element, Enhancer,Element, Genetic Enhancer,Elements, Enhancer,Elements, Genetic Enhancer,Enhancer Element,Enhancer Element, Genetic,Enhancer Sequence,Genetic Enhancer Element,Genetic Enhancer Elements,Sequence, Enhancer,Sequences, Enhancer
D005091	Exons	The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.	Mini-Exon,Exon,Mini Exon,Mini-Exons
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man