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Armstrong, G. A. B.

Publications and source records attributed to Armstrong, G. A. B..

2 recordsLinked to original sources

Loss of zebrafish dcst2 expression is not associated with muscle abnormalities

In this study we examined if the gene encoding Dendritic Cell-specific Six Transmembrane domain containing protein 2 (dcst2) plays a role in vertebrate muscle biology. Using the CRISPR/Cas9 mutagenic system we generated a 2 nucleotide deletion in exon 3 of the zebrafish ortholog dcst2 which resulted in a premature stop codon. Homozygous carriers of the mutation displayed reduced transcriptional expression of dcst2 suggesting that our mutation was indeed disrupting gene function. Mutant dcst2 zebrafish developed normally to adulthood and displayed no differences in motor function using a free-swim and swim tunnel assays. Furthermore, histological examination of muscle cells revealed no differences in slow-twitch or fast-twitch muscle cell cross-sectional area in our mutants. We did observe that dcst2-/- zebrafish were slightly heavier in weight and males were infertile. The data collected here, suggest that dcst2 does not play a role in zebrafish muscle cell biology.

molecular biology↗

Loss of mitochondrial Chchd10 or Chchd2 in zebrafish leads to an ALS-like phenotype and Complex I deficiency independent of the mt-ISR

Mutations in CHCHD10 and CHCHD2, coding for two paralogous mitochondrial proteins, have been identified in amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTD), and Parkinsons disease (PD). Here we investigated the biological roles of these proteins during vertebrate development using knockout (KO) models in zebrafish. We demonstrate that loss of either or both proteins leads to a motor impairment, reduced survival, and compromised neuromuscular junction (NMJ) integrity in larval zebrafish. Compensation by Chchd10 was observed in the chchd2-/- model, but not by Chchd2 in the chchd10 -/- model. The assembly of mitochondrial respiratory chain Complex I was impaired in chchd10 -/- and chchd2 -/- zebrafish larvae, but unexpectedly not in the double chchd10 -/- & chchd2 -/- model, suggesting that reduced mitochondrial Complex I cannot be solely responsible for the observed phenotypes, which are generally more severe in the double KO. Activation of the mitochondrial integrated stress response (mt-ISR) was only observed in the double KO model, possibly implicating this pathway in the recovery of the Complex I defect, and suggesting that Complex I assembly defect in our single KO is independent of the mt-ISR. Our results demonstrate that both proteins are required for normal vertebrate development, but their precise molecular function in the mitochondrial biology of motor neurons remains to be discovered.

developmental biology↗