Developmentally regulated alternative splicing generates a complex array of Drosophila para sodium channel isoforms

JR Thackeray; B Ganetzky

doi:10.1523/jneurosci.14-05-02569.1994

Alternative splicing potentiates dysfunction of early-onset epileptic encephalopathy SCN2A variants

The Journal of General Physiology ◽

10.1085/jgp.201912442 ◽

2020 ◽

Vol 152 (3) ◽

Cited By ~ 6

Author(s):

Christopher H. Thompson ◽

Roy Ben-Shalom ◽

Kevin J. Bender ◽

Alfred L. George

Keyword(s):

Alternative Splicing ◽

Sodium Channel ◽

Early Onset ◽

Neuronal Excitability ◽

Epileptic Encephalopathy ◽

Developmentally Regulated ◽

Voltage Gated Sodium Channel ◽

Splice Isoforms ◽

Voltage Gated ◽

Splice Isoform

Epileptic encephalopathies are severe forms of infantile-onset epilepsy often complicated by severe neurodevelopmental impairments. Some forms of early-onset epileptic encephalopathy (EOEE) have been associated with variants in SCN2A, which encodes the brain voltage-gated sodium channel NaV1.2. Many voltage-gated sodium channel genes, including SCN2A, undergo developmentally regulated mRNA splicing. The early onset of these disorders suggests that developmentally regulated alternative splicing of NaV1.2 may be an important consideration when elucidating the pathophysiological consequences of epilepsy-associated variants. We hypothesized that EOEE-associated NaV1.2 variants would exhibit greater dysfunction in a splice isoform that is prominently expressed during early development. We engineered five EOEE-associated NaV1.2 variants (T236S, E999K, S1336Y, T1623N, and R1882Q) into the adult and neonatal splice isoforms of NaV1.2 and performed whole-cell voltage clamp to elucidate their functional properties. All variants exhibited functional defects that could enhance neuronal excitability. Three of the five variants (T236S, E999K, and S1336Y) exhibited greater dysfunction in the neonatal isoform compared with those observed in the adult isoform. Computational modeling of a developing cortical pyramidal neuron indicated that T236S, E999K, S1336Y, and R1882Q showed hyperexcitability preferentially in immature neurons. These results suggest that both splice isoform and neuronal developmental stage influence how EOEE-associated NaV1.2 variants affect neuronal excitability.

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Conserved alternative splicing patterns and splicing signals in the Drosophila sodium channel gene para.

Genetics ◽

10.1093/genetics/141.1.203 ◽

1995 ◽

Vol 141 (1) ◽

pp. 203-214 ◽

Cited By ~ 3

Author(s):

J R Thackeray ◽

B Ganetzky

Keyword(s):

Alternative Splicing ◽

Sodium Channel ◽

Genomic Dna ◽

Specific Pattern ◽

Drosophila Virilis ◽

Cdna Clones ◽

Developmentally Regulated ◽

Gene Encoding ◽

Partial Cdna ◽

Site Consensus

Abstract We cloned genomic DNA corresponding to the Drosophila virilis homologue of para, a gene encoding a sodium channel alpha-subunit, and obtained many partial cDNA clones from embryos and adults. Para protein has been well conserved, and the optional elements at six different sites of alternative splicing in D. melanogaster are present in D. virilis, in addition to one new optional exon. Among 31 different splice-types observed in D. virilis, the stage-specific pattern of alternative splicing seen in D. melanogaster is also conserved. Comparison of genomic DNA sequence revealed three aspects that vary between alternatively and constitutively used exon sequences. Sixteen short blocks (10-75 bp), the only recognizably conserved intron sequence, were disproportionately associated with alternatively used splice sites. Silent site substitutions were found much less frequently in alternative than constitutive exon elements, and the degree of match to the Drosophila splice site consensus tended to be lower at less frequently selected alternative splice junctions. This study shows that the developmentally regulated variability of para products is highly conserved and therefore likely to be of functional significance and suggests that a variety of different sequence-dependent mechanisms may regulate this pattern of alternative splicing.

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Expression of Alternatively Spliced Sodium Channel α-Subunit Genes

Journal of Biological Chemistry ◽

10.1074/jbc.m406387200 ◽

2004 ◽

Vol 279 (44) ◽

pp. 46234-46241 ◽

Cited By ~ 88

Author(s):

Christopher K. Raymond ◽

John Castle ◽

Philip Garrett-Engele ◽

Christopher D. Armour ◽

Zhengyan Kan ◽

...

Keyword(s):

Alternative Splicing ◽

Sodium Channel ◽

Dorsal Root Ganglia ◽

Dorsal Root ◽

Genomic Sequence ◽

Molecular Medicine ◽

Primate Model ◽

Α Subunit ◽

Alternatively Spliced ◽

Splicing Patterns

Molecular medicine requires the precise definition of drug targets, and tools are now in place to provide genome-wide information on the expression and alternative splicing patterns of any known gene. DNA microarrays were used to monitor transcript levels of the nine well-characterized α-subunit sodium channel genes across a broad range of tissues from cynomolgus monkey, a non-human primate model. Alternative splicing of human transcripts for a subset of the genes that are expressed in dorsal root ganglia, SCN8A (Nav1.6), SCN9A (Nav1.7), and SCN11A (Nav1.9) was characterized in detail. Genomic sequence analysis among gene family paralogs and between cross-species orthologs suggested specific alternative splicing events within transcripts of these genes, all of which were experimentally confirmed in human tissues. Quantitative PCR revealed that certain alternative splice events are uniquely expressed in dorsal root ganglia. In addition to characterization of human transcripts, alternatively spliced sodium channel transcripts were monitored in a rat model for neuropathic pain. Consistent down-regulation of all transcripts was observed, as well as significant changes in the splicing patterns of SCN8A and SCN9A.

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Alternative Splicing of the Cardiac Sodium Channel in Pulmonary Arterial Hypertension

CHEST Journal ◽

10.1016/j.chest.2019.12.052 ◽

2020 ◽

Vol 158 (2) ◽

pp. 735-738 ◽

Cited By ~ 2

Author(s):

Debasree Banerjee ◽

Tom N. Grammatopoulos ◽

Amy Palmisciano ◽

James R. Klinger ◽

Ipsita Krishnan ◽

...

Keyword(s):

Alternative Splicing ◽

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Sodium Channel ◽

Cardiac Sodium Channel ◽

Pulmonary Arterial

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Developmentally Regulated Alternative Splicing of the α1(XI) Collagen Chain: Spatial and Temporal Segregation of Isoforms in the Cartilage of Fetal Rat Long Bones

Journal of Histochemistry & Cytochemistry ◽

10.1177/002215540004800601 ◽

2000 ◽

Vol 48 (6) ◽

pp. 725-741 ◽

Cited By ~ 24

Author(s):

Nicholas P. Morris ◽

Julia T. Oxford ◽

Gillian B.M. Davies ◽

Barbara F. Smoody ◽

Douglas R. Keene

Keyword(s):

Alternative Splicing ◽

Long Bones ◽

Developmentally Regulated ◽

Temporal Segregation ◽

Fetal Rat ◽

Collagen Chain

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Developmentally regulated expression, alternative splicing and distinct sub-groupings in members of the Schistosoma mansoni venom allergen-like (SmVAL) gene family

BMC Genomics ◽

10.1186/1471-2164-9-89 ◽

2008 ◽

Vol 9 (1) ◽

pp. 89 ◽

Cited By ~ 85

Author(s):

Iain W Chalmers ◽

Andrew J McArdle ◽

Richard MR Coulson ◽

Marissa A Wagner ◽

Ralf Schmid ◽

...

Keyword(s):

Alternative Splicing ◽

Schistosoma Mansoni ◽

Gene Family ◽

Developmentally Regulated ◽

Regulated Expression ◽

Venom Allergen

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Juvenile and mature MAP2 isoforms induce distinct patterns of process outgrowth.

Molecular Biology of the Cell ◽

10.1091/mbc.7.3.443 ◽

1996 ◽

Vol 7 (3) ◽

pp. 443-455 ◽

Cited By ~ 29

Author(s):

N Leclerc ◽

P W Baas ◽

C C Garner ◽

K S Kosik

Keyword(s):

Alternative Splicing ◽

Spodoptera Frugiperda ◽

Morphological Features ◽

Developmentally Regulated ◽

Architectural Elements ◽

Molecular Masses ◽

Process Outgrowth ◽

Cell Expression

Microtubule-associated protein-2 (MAP2) is the most abundant MAP in neurons, where its distribution is restricted to the somatodendritic compartment. This molecule undergoes developmentally regulated alternative splicing, resulting in at least two isoforms, a juvenile isoform (termed MAP2c) and a mature isoform (MAP2), with greatly different molecular masses. Spodoptera frugiperda (Sf9) cell expression of the juvenile versus the mature MAP2 isoform generates two distinct patterns of process outgrowth. The smaller juvenile isoform induces multiple short thin processes. Mature MAP2 tends to induce single processes that are considerably thicker than those processes induced by juvenile MAP2. We found important differences in the variability of spacing between microtubules and the number of microtubules along the processes induced by MAP2c and mature MAP2. MAP2c showed variability with most microtubules spaced as closely as with tau, but some spaced as far apart as with mature MAP2. Over their length, the mature MAP2 processes demonstrate proximo-distal taper, which corresponds to a narrowing of the spacing between microtubules from 90 nm to 40 nm. Moreover, there is a decreased number of microtubules in mature MAP2-induced processes whereas in tau and MAP2-induced processes, the number of microtubules is constant along the length. Based on these observations, we conclude that MAP2 isoforms can serve as architectural elements by establishing specific morphological features of processes and specific arrangements of their microtubules.

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