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Pivot Concepts:
Gene/Protein
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Target Concepts:
Gene/Protein
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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
An understanding of muscle structure and function is central to improving our knowledge of the group of muscle diseases referred to as muscular dystrophies. These diseases involve a progressive weakening and
wasting
of skeletal muscle, which can be associated with life-threatening cardiac arrhythmias. The vast majority of these diseases arise from defects in either cytoskeletal or structural proteins, resulting in a breakdown of muscle cell integrity. However, mutations in two nuclear proteins--emerin and lamin A/C--have also been demonstrated to give rise to a muscular dystrophy phenotype. In addition, mutations in lamin A/C can give rise to a dilated cardiomyopathy, a lipodystrophy or a neuropathy. It is far from clear how mutations in nuclear proteins can result in a dystrophy, or cause more than one clinically distinct disease. Understanding the functional role of nuclear proteins in causing these diseases will therefore provide novel insights into muscle function, and should hopefully provide new directions for treatment.
Expert Rev
Mol
Med 2002 Jul 30
PMID:Muscular dystrophies, dilated cardiomyopathy, lipodystrophy and neuropathy: the nuclear connection. 1458 57
Patients with Duchenne muscular dystrophy (DMD), an X-linked lethal muscle-
wasting
disease, have abnormal expression of the protein dystrophin within their muscle fibres. In the mdx mouse model of this condition, both germline and neonatal somatic gene transfers of dystrophin cDNAs have demonstrated the potential of gene therapy in treating DMD. However, in many DMD patients, there appears to be no dystrophin expression when muscle biopsies are immunostained or western blots are performed. This raises the possibility that the expression of dystrophin following gene transfer might trigger a destructive immune response against this 'neoantigen'. Immune responses can also be generated against the gene transfer vector used to transfect the dystrophic muscle, and the combined immune response could further damage the already inflamed muscle. These problems are now beginning to be investigated in immunocompetent mdx mice. Although much work remains to be done, there are promising indications that these immune responses might not prove as much of a concern as originally envisaged.
Expert Rev
Mol
Med 2002 Nov 04
PMID:Immunological hurdles in the path to gene therapy for Duchenne muscular dystrophy. 1458 59
Duchenne muscular dystrophy is an X-linked recessive disorder, primarily characterized by progressive muscle weakness and
wasting
. The disease results from the absence of dystrophin, however the precise molecular mechanisms leading to muscle pathology are poorly understood. Dystrophic muscles undergo increased oxidative stress and altered calcium homeostasis, which may contribute to myofiber loss by triggering both necrosis and apoptosis. Recent studies have identified ARC (apoptosis repressor with caspase recruitment domain) as an abundant protein in human muscle that can inhibit both hypoxia and caspase-8-induced apoptosis as well as protect cells from oxidative stress. To explore a potential role for ARC in protecting muscle fibers from dystrophic breakdown, we have cloned and characterized murine ARC and studied its expression in normal and dystrophic mouse muscle. ARC is expressed at high levels in striated muscle and displays fiber-type restricted expression patterns. ARC expression levels are normal in dystrophic mdx mice, although the intracellular localization pattern of ARC is slightly altered compared with normal muscles. Overexpression of ARC in transgenic mdx mice failed to alleviate the dystrophic pathology in skeletal muscles, suggesting that misregulation of the molecular pathways regulated by ARC does not significantly contribute to myofiber death.
Hum
Mol
Genet 2004 Jan 15
PMID:Characterization of ARC, apoptosis repressor interacting with CARD, in normal and dystrophin-deficient skeletal muscle. 1464 4
Cycloheximide acts at the large subunit of the ribosome to inhibit translation. Here we report that ubiquitin levels are critical for the survival of Saccharomyces cerevisiae cells in the presence of cycloheximide: ubiquitin overexpression confers resistance to cycloheximide, while a reduced ubiquitin level confers sensitivity. Consistent with these findings, ubiquitin is unstable in yeast (t(1/2) = 2 h) and is rapidly depleted upon cycloheximide treatment. Cycloheximide does not noticeably enhance ubiquitin turnover, but serves principally to block ubiquitin synthesis. Cycloheximide also induces UBI4, the polyubiquitin gene. The cycloheximide-resistant phenotype of ubiquitin overexpressors is also characteristic of partial-loss-of-function proteasome mutants. Ubiquitin is stabilized in these mutants, which may account for their cycloheximide resistance. Previous studies have reported that ubiquitin is destabilized in the absence of Ubp6, a proteasome-associated deubiquitinating enzyme, and that ubp6 mutants are hypersensitive to cycloheximide. Consistent with the model that cycloheximide-treated cells are ubiquitin deficient, the cycloheximide sensitivity of ubp6 mutants can be rescued either by ubiquitin overexpression or by mutations in proteasome subunit genes. These results also show that ubiquitin
wasting
in ubp6 mutants is proteasome mediated. Ubiquitin overexpression rescued cells from additional translational inhibitors such as anisomycin and hygromycin B, suggesting that ubiquitin depletion may constitute a widespread mechanism for the toxicity of translational inhibitors.
Mol
Cell Biol 2003 Dec
PMID:Ubiquitin depletion as a key mediator of toxicity by translational inhibitors. 1464 27
Congenital adrenal hyperplasia (CAH) refers to a family of inherited disorders of adrenal steroidogenesis in which each disorder is characterized by a specific enzyme deficiency that impairs cortisol production by the adrenal cortex. The enzymes most commonly affected are 21-hydroxylase (21-OH), 11beta-hydroxylase, 3beta-hydroxysteroid dehydrogenase, and less often, 17alpha-hydroxylase/17,20-lyase and cholesterol desmolase. Many of the corresponding genes for the described enzymes have been isolated and characterized, and specific mutations causing CAH have been identified. In classical CAH (simple virilizing and salt
wasting
forms), androgen excess causes external genital ambiguity in newborn females and progressive postnatal virilization in both sexes. In nonclassical CAH, 21-OHD is partial and occurs with milder symptoms. A deficiency of 11beta-Hydroxylase deficiency results in ambiguous genitalia in the newborn genetic female and androgen excess and hypertension in both males and females. In 3beta-hydroxysteroid deficiency adrenal and gonadal androgen production is deficient resulting in incomplete genital development in genetic males and limited androgen affect in females. Two less frequent causes of CAH 17alpha-Hydroxylase/17,20-lyase and cholesterol desmolase result in external female genitalia in both sexes. Hormonal diagnosis is described for each disorder.
Mol
Cell Endocrinol 2003 Dec 15
PMID:Inborn errors of adrenal steroidogenesis. 1465 79
TNF-alpha is a pro-inflammatory cytokine that plays a key role in disorders due to HIV-1 infection and replication such as Kaposi sarcoma,
wasting
, aphthous ulcerations and progression to AIDS. The controversial drug thalidomide is anti-inflammatory, anti-angiogenic and a selective inhibitor of TNF-alpha that is being studied as a treatment for HIV-1-related disorders, immune disorders and cancer. The cellular and molecular mechanism of thalidomide is unclear despite renewed clinical interest in the drug. Previous data from this laboratory indicate that thalidomide decreases cell growth and cell-cell interactions of human T leukemic cells. The specific aim of the present study is to determine whether thalidomide administration induces cell death via apoptosis. Low dose thalidomide treatment of human T leukemic cells exhibited rapid increases in caspase-3 activity, annexin V-FITC binding and DNA disintegration that is characteristic of apoptosis. These data indicate that low doses of thalidomide signal human T leukemic cells to die by apoptosis, which is a possible method of altering inflammatory cells and inflammatory activities.
Cell
Mol
Biol (Noisy-le-grand) 2003 Nov
PMID:Exposure to the anti-TNF-alpha drug thalidomide induces apoptotic cell death in human T leukemic cells. 1468 94
Our previous studies indicate that hearts from septic rats have decreased work with oxygen
wasting
. The present studies test if there is energy deficit, changes in cardiac mitochondrial content and caspase activation during sepsis. Anesthetized, male Sprague-Dawley rats received no surgical treatment (control), laparotomy (sham), or laparotomy with cecal ligation and puncture (CLP) to induce polymicrobial septic shock. Hearts were isolated 12-14 h later. Cardiac work, oxygen consumption, substrate oxidation and energy stores were measured in perfused hearts. Normalized density of mitochondria was determined in ventricles without perfusion by morphometric analysis with electron microscopy. Citrate synthase activity was assessed in homogenates and isolated mitochondria. Cardiac work decreased significantly in CLP (47%), while oxygen consumption and glucose oxidation were unchanged compared with control or sham hearts (oxygen and substrate
wasting
). Tissue adenosine triphosphate, creatine phosphate and glycogen were lower in CLP hearts (energy deficit). Mitochondrial grid intersects decreased significantly from 151 +/- 8 sham to 130 +/- 4 CLP out of 361 possible intersects and autophagy was observed in CLP hearts. Total activity of citrate synthase decreased in homogenates (99 +/- 8 micromol/min/g wet weight sham vs. 62 +/- 7 CLP, P < 0.05) and in the mitochondrial fraction (27 +/- 1 micromol/min/g wet weight sham to 22 +/- 1 CLP, P < 0.05). Calculated mitochondrial content decreased from 63 +/- 4 mg protein/g wet weight sham to 46 +/- 5 CLP, P < 0.05 (mitochondrial depletion). Caspase-3 activity doubled and tumor necrosis factor alpha content tripled in CLP hearts. CONCLUSIONS. - Oxygen and substrate
wasting
in CLP occurs with fewer mitochondria and energy deficit, processes that are coincident with caspase-3 activation.
J
Mol
Cell Cardiol 2004 Jan
PMID:Metabolic dysfunction and depletion of mitochondria in hearts of septic rats. 1473 56
Myotonic dystrophy (DM1) is a multisystemic disorder caused by a CTG repeat expansion within the 3'-UTR of the DMPK gene. DM1 is characterized by delayed muscle development, muscle weakness and
wasting
, cardiac conduction abnormalities, cognitive defects and cataracts. Recent studies have demonstrated that the disease mechanism involves a dominant gain-of-function conferred upon mutant transcripts by expanded repeats. However, further attempts to model aspects of DM muscle pathology in cultured myoblasts suggest that 3'-UTR sequences flanking the CTG repeat tract are also required for full expression of the disease phenotype. Here, we report that overexpression of the DMPK 3'-UTR including either wild-type (11) or expanded (91) CTG repeats results in aberrant and delayed muscle development in fetal transgenic mice. In addition, transgenic animals with both expanded and wild-type CTG repeats display muscle atrophy at 3 months of age. Primary myoblast cultures from both 11 and 91 repeat mice display reduced fusion potential, but a greater reduction is observed in the 91 repeat cultures. Taken together, these data indicate that overexpression of the DMPK 3'-UTR interferes with normal muscle development in mice and that this is exacerbated by inclusion of a mutant repeat. This suggests that the delayed muscle development in DM1 involves an interplay between the expanded CTG repeat and adjacent 3'-UTR sequences.
Hum
Mol
Genet 2004 Mar 15
PMID:Inhibition of myogenesis in transgenic mice expressing the human DMPK 3'-UTR. 1473 27
Busy diagnosticians need to know what is useful, and what is dross, when dealing with the internet. From the comprehensive array of resources that characterizes the offerings available via the world wide web and email correspondence, in particular, this chapter seeks to identify the most useful tools for the diagnostics laboratory. With rapid communications and fast internet consultations only a few keystrokes away, there really is no point in
wasting
time on fruitless searches when professionals are so accessible. But accessibility carries the weight of responsibility as well, and communications must be engaged with a fair modicum of civility and common courtesy. Responsibility is a crucially important component of public or semiprivate communication in terms of your own identity, and that of the organization that you represent. Recognition of the relative vulnerability of individual machines to the worldwide disseminated computer viruses, worms, or trojan horses currently abounding, for example, is perhaps the most important step in your approach to security issues, but this recognition must go hand in hand with institutional steps to protect the organization of which you are a part. Organizational tools that serve the diagnostician well in the laboratory can also be mobilized in the aid of communications through the net, and always that harbinger of understanding, common sense, should prevail in one's dealings both with machines, and the people who are communicating either directly or indirectly through them.
Methods
Mol
Med 2004
PMID:Molecular diagnostics resources on the Internet. 1495 42
Type I pseudohypoaldosteronism (PHA1) is a rare form of mineralocorticoid resistance characterized by neonatal renal salt
wasting
and failure to thrive. Typical biochemical features include high levels of plasma aldosterone and renin, hyponatremia and hyperkalemia. Different mutations of the human mineralocorticoid receptor (hMR) gene have been identified in subjects affected by the autosomal dominant or sporadic form of the disease. Our laboratory has investigated a large number of subjects with familial and sporadic PHA1. Several different mutations have been detected, which are localized in different coding exons of the hMR gene. These mutations either create truncated proteins, either affect specific amino acids involved in receptor function. In this paper, we review hMR mutations described to date in PHA1 and their functional characterization. We discuss the absence of mutations in some kindreds and the role of precise phenotypic and biological examination of patients to allow for identification of other genes potentially involved in the disease.
Mol
Cell Endocrinol 2004 Mar 31
PMID:Inactivating mutations of the mineralocorticoid receptor in Type I pseudohypoaldosteronism. 1513 10
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