Pseudouridine synthase 1 deficient mice, a model for Mitochondrial Myopathy with Sideroblastic Anemia, exhibit muscle morphology and physiology alterations
نویسندگان
چکیده
Mitochondrial myopathy with lactic acidosis and sideroblastic anemia (MLASA) is an oxidative phosphorylation disorder, with primary clinical manifestations of myopathic exercise intolerance and a macrocytic sideroblastic anemia. One cause of MLASA is recessive mutations in PUS1, which encodes pseudouridine (Ψ) synthase 1 (Pus1p). Here we describe a mouse model of MLASA due to mutations in PUS1. As expected, certain Ψ modifications were missing in cytoplasmic and mitochondrial tRNAs from Pus1(-/-) animals. Pus1(-/-) mice were born at the expected Mendelian frequency and were non-dysmorphic. At 14 weeks the mutants displayed reduced exercise capacity. Examination of tibialis anterior (TA) muscle morphology and histochemistry demonstrated an increase in the cross sectional area and proportion of myosin heavy chain (MHC) IIB and low succinate dehydrogenase (SDH) expressing myofibers, without a change in the size of MHC IIA positive or high SDH myofibers. Cytochrome c oxidase activity was significantly reduced in extracts from red gastrocnemius muscle from Pus1(-/-) mice. Transmission electron microscopy on red gastrocnemius muscle demonstrated that Pus1(-/-) mice also had lower intermyofibrillar mitochondrial density and smaller mitochondria. Collectively, these results suggest that alterations in muscle metabolism related to mitochondrial content and oxidative capacity may account for the reduced exercise capacity in Pus1(-/-) mice.
منابع مشابه
Mitochondrial myopathy and sideroblastic anemia (MLASA): missense mutation in the pseudouridine synthase 1 (PUS1) gene is associated with the loss of tRNA pseudouridylation.
A missense mutation in the PUS1 gene affecting a highly conserved amino acid has been associated with mitochondrial myopathy and sideroblastic anemia (MLASA), a rare autosomal recessive oxidative phosphorylation disorder. The PUS1 gene encodes the enzyme pseudouridine synthase 1 (Pus1p) that is known to pseudouridylate tRNAs in other species. Total RNA was isolated from lymphoblastoid cell line...
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عنوان ژورنال:
دوره 6 شماره
صفحات -
تاریخ انتشار 2016