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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RNA interference (RNAi) is a mechanism that appears to control unwanted gene expression in a wide range of species. In Drosophila, RNAi is most effectively induced by double-stranded RNAs (dsRNAs) of over approximately 80 nucleotides (nt) and in mammalian cells an RNAi-like inhibition of gene expression has been shown to be mediated by dsRNAs of approximately 21-23 nt. To test if RNAi can be used to specifically down-regulate a human disease-related transcript we have used Drosophila and human tissue culture models of the dominant genetic disorder spinobulbar muscular atrophy (SBMA). A variety of different dsRNAs were assessed for the ability to inhibit expression of transcripts that included a truncated human androgen receptor (ar) gene containing different CAG repeat lengths (16-112 repeats). In Drosophila cells, dsRNAs corresponding to non-repetitive sequences mediated a high degree of sequence-specific inhibition, whereas RNA duplexes containing CAG repeat tracts only induced gene-specific inhibition when flanking ar sequences were included; dsRNAs containing various lengths of CAG repeats plus ar sequences were unable to induce allele-specific interference. In mammalian cells we tested sequence-specific small dsRNAs of 22 nt; these rescued the toxicity and caspase-3 activation induced by plasmids expressing a transcript encoding an expanded polyglutamine tract. This study demonstrates the feasibility of targeting a transcript associated with an important group of genetic diseases by RNAi.
Hum Mol Genet 2002 Jan 15
PMID:Rescue of polyglutamine-mediated cytotoxicity by double-stranded RNA-mediated RNA interference. 1180 26

Chediak-Higashi syndrome is a genetic disorder caused by mutations in a gene encoding a protein named LYST in humans ("lysosomal trafficking regulator") or Beige in mice. A prominent feature of this disease is the accumulation of enlarged lysosome-related granules in a variety of cells. The genome of Dictyostelium discoideum contains six genes encoding proteins that are related to LYST/Beige in amino acid sequence, and disruption of one of these genes, lvsA (large volume sphere), results in profound defects in cytokinesis. To better understand the function of this family of proteins in membrane trafficking, we have analyzed mutants disrupted in lvsA, lvsB, lvsC, lvsD, lvsE, and lvsF. Of all these, only lvsA and lvsB mutants displayed interesting phenotypes in our assays. lvsA-null cells exhibited defects in phagocytosis and contained abnormal looking contractile vacuole membranes. Loss of LvsB, the Dictyostelium protein most similar to LYST/Beige, resulted in the formation of enlarged vesicles that by multiple criteria appeared to be acidic lysosomes. The rates of endocytosis, phagocytosis, and fluid phase exocytosis were normal in lvsB-null cells. Also, the rates of processing and the efficiency of targeting of lysosomal alpha-mannosidase were normal, although lvsB mutants inefficiently retained alpha-mannosidase, as well as two other lysosomal cysteine proteinases. Finally, results of pulse-chase experiments indicated that an increase in fusion rates accounted for the enlarged lysosomes in lvsB-null cells, suggesting that LvsB acts as a negative regulator of fusion. Our results support the notion that LvsB/LYST/Beige function in a similar manner to regulate lysosome biogenesis.
Mol Biol Cell 2002 Feb
PMID:Dictyostelium LvsB mutants model the lysosomal defects associated with Chediak-Higashi syndrome. 1185 20

Tuberous sclerosis (TSC) is a autosomal dominant genetic disorder caused by mutations in either TSC1 or TSC2, and characterized by benign hamartoma growth. We developed a murine model of Tsc1 disease by gene targeting. Tsc1 null embryos die at mid-gestation from a failure of liver development. Tsc1 heterozygotes develop kidney cystadenomas and liver hemangiomas at high frequency, but the incidence of kidney tumors is somewhat lower than in Tsc2 heterozygote mice. Liver hemangiomas were more common, more severe and caused higher mortality in female than in male Tsc1 heterozygotes. Tsc1 null embryo fibroblast lines have persistent phosphorylation of the p70S6K (S6K) and its substrate S6, that is sensitive to treatment with rapamycin, indicating constitutive activation of the mTOR-S6K pathway due to loss of the Tsc1 protein, hamartin. Hyperphosphorylation of S6 is also seen in kidney tumors in the heterozygote mice, suggesting that inhibition of this pathway may have benefit in control of TSC hamartomas.
Hum Mol Genet 2002 Mar 01
PMID:A mouse model of TSC1 reveals sex-dependent lethality from liver hemangiomas, and up-regulation of p70S6 kinase activity in Tsc1 null cells. 1187 47

Bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by growth deficiency, unusual facies, sun-sensitive telangiectatic erythema, immunodeficiency and predisposition to cancer. The causative gene for BS is the BLM gene which encodes the BLM RecQ helicase protein. The BLM gene has 4437 bp and encodes 1417 amino acids. The detection of BLM gene mutations for laboratory diagnosis of BS is laborious and impractical, unless there are common mutations in a population. Here we describe the immunoblot and immunohistochemical analyses for the detection of the BLM protein using a polyclonal BLM antibody. The BLM gene and protein were consistently and clearly detected in Epstein-Barr virus (EBV)-transformed or phytohemagglutinin (PHA)-stimulated lymphoblasts from control and various human hematopoietic cell lines. In a 7-week old human fetal brain, the BLM gene expression was strongly detected in contrast to an adult human brain. The BLM protein was not detected in EBV-transformed lymphoblasts from three BS patients. By immunohistochemistry, nuclear dots of the BLM protein were detected in both EBV-transformed lymphoblasts and PHA-stimulated lymphoblasts from the control. However, in lymphoblasts from BS patients no nuclear dots of the BLM protein were detected. These results indicate that the combinational analysis of immunoblotting and immunohistochemistry is a useful approach to screening of BS, although a mutation analysis is necessary for a definitive diagnosis of BS.
Int J Mol Med 2002 Jul
PMID:Expression of BLM (the causative gene for Bloom syndrome) and screening of Bloom syndrome. 1206 Aug 58

Transcobalamin II (TCII) is a plasma protein essential for the transport and cellular uptake of vitamin B12 (B12; cobalamin, Cbl). Congenital deficiency of functional TCII is an autosomal recessive genetic disorder that results in clinical B12 deficiency usually within several months following birth. In this report, we describe the molecular basis for TCII deficiency in two patients who developed a megaloblastic anemia in early infancy. The serum of both patients contained immunoreactive TCII that did not bind [57Co]Cbl. The fibroblasts from each patient secreted a similarly nonfunctional TCII, yet full-length TCII transcripts were identified by Northern blot. Overlapping cDNA fragments were generated by reverse transcription-polymerase chain reaction and several mutations were identified in the coding region of the cDNA, one of which was common to both patients. However, amplification of the corresponding regions of the gene from genomic DNA failed to identify these mutations. These findings were confirmed by replicate analyses and support the proposal that a variance in RNA editing is the likely mechanism for the mutations that resulted in the expression of a nonfunctional TCII protein in these patients.
Blood Cells Mol Dis
PMID:Congenital transcobalamin II deficiency due to errors in RNA editing. 1206 7

Deficiency in a coagulation factor VIII (FVIII) causes a genetic disorder hemophilia A, which is treated by repeated infusions of expensive FVIII products. Recombinant FVIII (rFVIII), the culmination of years of extensive international research, is an important alternative to plasma-derived FVIII (pdFVIII) and is considered to have a higher margin of safety. Advances in biotechnology allowed production of rFVIII at industrial scale, which significantly improved treatment of hemophilia A patients. We review the contemporary methods used for FVIII expression in mammalian cell culture systems and discuss the factors responsible for insufficient recoveries of rFVIII, such as inefficient accumulation of FVIII mRNA in the cell, complexity of the mechanisms of FVIII secretion, and instability of secreted FVIII. The approaches to improve the yield of rFVIII in cell culture systems include genetic engineering of B-domain-deleted FVIII, introduction of introns into FVIII cDNA constructs for more efficient processing and accumulation of FVIII mRNA, and introduction of mutations into chaperone-binding sites of FVIII to improve its secretion. Design of FVIII with prolonged half-life in vivo is considered as another promising direction in improving rFVIII protein and efficiency of hemophilia A therapy. As an alternative to expression of rFVIII in cell culture systems, we discuss production of rFVIII in transgenic animals, where high levels of rFVIII have been successfully secreted into milk. We also pay attention to the major limitations of this approach, such as safety issues associated with potential transmission of animal pathogens. Finally, we present a brief characterization of commercial recombinant FVIII products currently available on the market for hemophilia A treatment.
Blood Cells Mol Dis
PMID:Expression of factor VIII in recombinant and transgenic systems. 1206 19

Among all vectors designed for gene therapy purposes, adenovirus appears to be the most efficient in vivo vehicle to transduce the broadest spectrum of cellular targets. However, the deleterious immunogenicity of this viral vector impedes its use in chronic diseases. Non-viral vectors, such as naked DNA, are attractive alternatives for safety and technical issues, such as scale-up production. Naked DNA injection, greatly improved when combined with electroporation, showed great potential in adult animals, especially when directed to the muscle. We have recently proven the therapeutic effect of a neonatal single intramuscular injection of a cardiotrophin-1 (CT-1)-encoding adenovirus in a hereditary disease mouse model of human motor neuron disease, the progressive motor neuronopathy (pmn) mutant. We now demonstrate that a single injection/electroporation of a CT-1-encoding plasmid in neonate pmn mice is almost as efficient as adenovirus-mediated gene transfer with respect to survival, muscular function and neuroprotection of the animals. Treated mice gain global weight, their mean lifespan is extended by 25%, all their electromyographic parameters are improved and myelinated axons of their phrenic nerves are protected. Moreover, we show that re-injection/electroporation leads to improvements in this neuroprotection. We therefore demonstrate for the first time the therapeutic efficacy of neonatal intramuscular DNA injection/electroporation in a murine model of a human hereditary disorder.
Hum Mol Genet 2002 Jul 01
PMID:In vivo electrotransfer of the cardiotrophin-1 gene into skeletal muscle slows down progression of motor neuron degeneration in pmn mice. 1207 6

Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by cardiac hypertrophy caused by mutations in genes encoding sarcomere proteins. This study screened all patients with HCM from the Kuopio University Hospital region in eastern Finland for variants in the cardiac myosin-binding protein C gene ( MYBPC3). All 35 exons of MYBPC3 were screened by the single-strand conformation polymorphism method in 37 unrelated patients with HCM. In MYBPC3 we identified seven novel (Gln1061X, IVS5-2A-->C, IVS14-13G-->A, Ex25DeltaLys, Pro147Leu, Ser236Gly, and Arg1138His) and two previously reported (Arg326Gln, Val896Met) variants, all of which are predicted to affect the structure of the encoded protein. Four of the nine variants, a nonsense mutation Gln1061X, a splice acceptor mutation (IVS5-2A-->C), a novel substitution in intron 14 (IVS14-13G-->A), and a novel 3-bp deletion in exon 25 (Ex25DeltaLys) were concluded to be disease-causing mutations because they cosegregated with the HCM phenotype or were absent in more than 200 normal chromosomes, or both. The mutation Gln1061X was found most frequently, being present in 6 families (23 subjects) while the other three mutations were found in single families each. Haplotype analysis indicated a likely founder effect among the families carrying the Gln1061X mutation. We found four novel mutations in MYBPC3, accounting for approx. 38% of familial and 24% of all cases of HCM. In our previous and unpublished studies no more frequent cause of HCM has been found in genetic analyses of other eight sarcomeric proteins. Consequently MYBPC3 is the predominant gene for HCM in eastern Finland. In addition, several amino acid substitutions in MYBPC3 suspected to be not associated with HCM were identified, indicating that some of the missense variants found in MYBPC3 are possibly not disease-causing mutations.
J Mol Med (Berl) 2002 Jul
PMID:Mutations in the cardiac myosin-binding protein C gene are the predominant cause of familial hypertrophic cardiomyopathy in eastern Finland. 1211 Sep 47

ICF syndrome (immunodeficiency, centromere instability and facial anomalies) is a recessive human genetic disorder resulting from mutations in the DNA methyltransferase 3B (DNMT3B) gene. Patients with this disease exhibit numerous chromosomal abnormalities, including anomalous decondensation, pairing, separation and breakage, primarily involving the pericentromeric regions of chromosomes 1 and 16. Global levels of DNA methylation in ICF cells are only slightly reduced; however, certain repetitive sequences and genes on the inactive X chromosome of female ICF patients are significantly hypomethylated. In the present report, we analyze the molecular defect of de novo methylation in ICF cells in greater detail by making use of a model Epstein-Barr virus (EBV)-based system and three members of the unique cellular cancer-testis (C-T) gene family. Results with the EBV-based system indicate that de novo methylation of newly introduced viral sequences is defective in ICF syndrome. Limited de novo methylation capacity is retained in ICF cells, indicating that the mutations in DNMT3B are not complete loss-of-function mutations or that other DNMTs cooperate with DNMT3B. Analysis of three C-T genes (two on the X chromosome and one autosomal) revealed that loss of methylation from cellular gene sequences is heterogeneous, with both autosomal and X chromosome-based genes demonstrating sensitivity to mutations in DNMT3B. Aberrant hypomethylation at a number of loci examined correlated with altered gene expression levels. Lastly, no consistent changes in the protein levels of the DNA methyltransferases were noted when normal and ICF cell lines were compared.
Hum Mol Genet 2002 Sep 01
PMID:Defective de novo methylation of viral and cellular DNA sequences in ICF syndrome cells. 1218 61

Hirschsprung disease (HSCR), or congenital intestinal aganglionosis, is a common hereditary disorder causing intestinal obstruction, thereby showing considerable phenotypic variation in conjunction with complex inheritance. Moreover, phenotypic assessment of the disease has been complicated since a subset of the observed mutations is also associated with several additional syndromic anomalies. Coding sequence mutations in e.g. RET, GDNF, EDNRB, EDN3, and SOX10 lead to long-segment (L-HSCR) as well as syndromic HSCR but fail to explain the transmission of the much more common short-segment form (S-HSCR). Furthermore, mutations in the RET gene are responsible for approximately half of the familial and some sporadic cases, strongly suggesting, on the one hand, the importance of non-coding variations and, on the other hand, that additional genes involved in the development of the enteric nervous system still await their discovery. For almost all of the identified HSCR genes incomplete penetrance of the HSCR phenotype has been reported, probably due to modifier loci. Therefore, HSCR has become a model for a complex oligo-/polygenic disorder in which the relationship between different genes creating a non-mendelian inheritance pattern still remains to be elucidated.
Int J Mol Med 2002 Oct
PMID:Hirschsprung, RET-SOX and beyond: the challenge of examining non-mendelian traits (Review). 1223 80


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