Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report two siblings with a relatively severe limb-girdle muscular dystrophy. The elder sister presented at 8 years of age with inability to climb and abnormal gait. At 12 years she was barely ambulant. Her sister followed a similar course. Serum creatine kinase was 8500-10000 IU (N 25-200) in the elder sister and 17000-19000 IU in the younger sister. Muscle biopsy of the elder sister at 8 years showed chronic myopathic changes with loss of muscle fibres, active necrosis and regeneration. Immunocytochemistry demonstrated normal spectrin and dystrophin, reduced alpha-sarcoglycan and absent gamma-sarcoglycan--indicating a gamma-sarcoglycanopathy. Haplotype analysis for the markers D13S115, D13S232, D13S292, D13S787, D13S1243 and D13S283 internal to and flanking the gamma-sarcoglycan gene showed the affected sisters shared haplotypes, indicating it was possible they were suffering from a gamma-sarcoglycanopathy. Non-inheritance of paternal alleles for D13S232, D13S292 and D13S1243 suggested the inheritance of a deletion, which was confirmed by FISH, using a genomic probe from the gamma-sarcoglycan gene. The gamma-sarcoglycan cDNA was amplified by reverse transcriptase PCR from the muscle biopsy of the elder sister and sequenced. A missense mutation changing codon 69 from GGC glycine to CGC arginine was identified. HhaI digestion of exon 3 genomic PCR products showed the two affected sisters were hemizygous for the mutation, while the mother and grandmother were heterozygotes. The mutation, identified by SSCP analysis, was not observed in 116 unrelated, unaffected individuals. Previously, only two other missense mutations, the Cys283Tyr missense mutation in Gypsies and the Leu193Ser mutation in a Dutch family, have been described in the gamma-sarcoglycan gene. The fact that the affected individuals in the current and Gypsy families are gamma-sarcoglycan negative may indicate that codons 69 and 283 are important in gamma-sarcoglycan function.
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PMID:Severe gamma-sarcoglycanopathy caused by a novel missense mutation and a large deletion. 1071 84

Dysferlin is a protein of the sarcolemma that is mutated in patients with limb girdle muscular dystrophy 2B, Miyoshi myopathy, and distal anterior myopathy. It has been implicated in muscle signaling and sarcolemma repair. To further understand its functional role we studied dysferlin expression in satellite cells (SCs) in normal and pathological human muscle biopsies, as well as in primary cultures of human skeletal muscle. Using immunohistochemistry we detected dysferlin-positive (Dysf+) SCs. Double staining with c-met+, a total SC marker, showed that the number of Dysf+ SCs ranged from 33.7% +/- 4.4% in normal muscle to 68.0% +/- 6.2% in pathological muscles, whereas double staining with MyoD/Dysf showed that all activated SC (MyoD+) were also Dysf+. These results indicate that dysferlin is upregulated in activated SCs. In vitro, immunohistochemistry, semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), and real-time PCR showed that both dysferlin mRNA and protein expression were higher in multinucleated myotubes than in the myoblast stage (p < 0.05). Furthermore, experiments of inhibition of myoblast fusion with amiloride, a type T calcium channel antagonist, showed that dysferlin levels were lower in treated than in non-treated cultures (p < 0.001), demonstrating that dysferlin expression reached peak levels upon differentiation into myotubes. These results and the in vivo findings of dysferlin expression when SCs are activated confirm the involvement of dysferlin in human muscle regeneration/repair and its possible role in fusion events during muscle development.
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PMID:In vivo and in vitro dysferlin expression in human muscle satellite cells. 1553 37

Recently, participation of the sarcoglycan (SG)-sarcospan (SSPN) complex in the development of cardiomyopathy in patients with limb-girdle muscular dystrophy has been shown, and presence of the complex in smooth muscle may be important for the contraction/dilation process of vessels. However, there are few studies determining the SG-SSPN complex in vascular smooth muscle and endothelial cells of vessels. In this study, we analyzed by reverse transcriptase-polymerase chain reaction and immunofluorescence the expression of different components of the complex in vein/artery smooth muscle and endothelial cells of the human umbilical cord. By RNA analysis, we observed expression of alpha-, beta-, gamma-, delta-, epsilon-SG, and SSPN in smooth muscle cells. In endothelial cells, RNA expression was restricted to beta-, delta-, epsilon-SG, and SSPN. At protein level, we observed in smooth muscle the presence of beta-, delta-, epsilon-SG, and SSPN. In endothelial cells, immunostaining only evidenced the presence of epsilon-SG and SSPN. However, colocalization of SGs and SSPN with dystrophin and utrophin was noted. These results, interestingly, suggest that the SG-SSPN complex may either form with dystrophin or utrophin in smooth muscle cells, and with utrophin in endothelial cells. Additionally, we also observed in some smooth muscle regions the colocalization of the SG-SSPN complex with caveolin, with colocalization being more pronounced between epsilon-SG-SSPN and caveolin in endothelial cells.
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PMID:Expression analysis of the SG-SSPN complex in smooth muscle and endothelial cells of human umbilical cord vessels. 1558 76

The limb-girdle muscular dystrophy type 2A (LGMD2A) is a recessively inherited disease caused by a mutation of the calpain 3 gene (CAPN3), and is considered one of the most prevalent subtypes of limb-girdle muscular dystrophy (LGMD). In this study, we aimed to identify CAPN3 mutations and to characterize the phenotype of Korean patients with LGMD2A. Among 35 patients with LGMD, four patients, who showed calpain 3 deficiency on western blot analysis, were analyzed in this study. Total RNA extracted from frozen muscle tissue was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using six primer pairs covering all coding sequences of CAPN3, and direct sequencing was performed. Clinical and pathological features of the patients were also reviewed. We found four different mutations in five alleles from three patients. Of the pathogenic mutations identified, two were novel (c.2125T>C and c.2355-2357delTTC), and the others had been reported elsewhere (c.440G>C, c.1076C>T). All patients showed a high CK level with predominant proximal leg weakness, and the onset was in their childhood except for one patient. Among two novel CAPN3 mutations, one was a missense mutation (c.2125T>C [p.709Ser>Pro]), and the other was a small in-frame deletion causing omission of a single amino acid (c.2355-2357delTTC [p.786delPhe]). The clinical features of our patients were generally compatible with the characteristics of LGMD2A patients described in the previous studies.
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PMID:Mutations of CAPN3 in Korean patients with limb-girdle muscular dystrophy. 1759 55