Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder caused by mutations in MECP2, encoding methyl-CpG-binding protein 2. MeCP2 is a transcriptional repressor elevated in mature neurons and is predicted to be required for neuronal maturation by regulating multiple target genes. Identifying primary gene targets in either Mecp2-deficient mice or human RTT brain has proven to be difficult, perhaps because of the transient requirement for MeCP2 during neuronal maturation. In order to experimentally control the timing of MeCP2 expression and deficiency during neuronal maturation, human SH-SY5Y cells undergoing mature neuronal differentiation were transfected with methylated MeCP2 oligonucleotide decoy to disrupt the binding of MeCP2 to endogenous targets. Genome-wide expression microarray analysis identified all four known members of the inhibitors of differentiation or inhibitors of DNA-binding (ID1, ID2, ID3 and ID4) subfamily of helix-loop-helix genes as novel neuronal targets of MeCP2. Chromatin immunoprecipitation analysis confirmed binding of MeCP2 near or within the promoters of ID1, ID2 and ID3, and quantitative RT-PCR confirmed increased expression of all four Id genes in Mecp2-deficient mouse brain. All four ID proteins were significantly increased in Mecp2-deficient mouse and human RTT brain using immunofluorescence and laser scanning cytometric analyses. Because of their involvement in cell differentiation and neural development, ID genes are ideal primary targets for MeCP2 regulation of neuronal maturation that may explain the molecular pathogenesis of RTT.
Hum Mol Genet 2006 Jun 15
PMID:Inhibitors of differentiation (ID1, ID2, ID3 and ID4) genes are neuronal targets of MeCP2 that are elevated in Rett syndrome. 1668 35

Rett syndrome (RTT) is a neurodevelopmental disorder characterized by cognitive regression, loss of purposeful hand movements and speech, stereotypies, ataxia, seizures, mental retardation and acquired microcephaly. Mutations in MECP2, encoding methyl-CpG-binding protein 2, are responsible for approximately 90% of classic RTT cases. RTT displays phenotypic overlap with Angelman syndrome, a disorder caused by loss of expression of the imprinted gene UBE3A. MeCP2 binds to methylated DNA and may alter the expression of imprinted genes, thereby suggesting a mechanistic link between the two disorders. Here, we tested the hypothesis that MeCP2 deficiency affects expression of Ube3a in mouse models of RTT. As Ube3a is only imprinted in brain, we evaluated Ube3a expression in brains of 15 different litters of neonatal or 8-week-old male Mecp2 mutant mice by real-time quantitative RT-PCR and western blot analysis. We found no significant differences between Mecp2(tm1.1Bird/Y) or Mecp2(tm1.1Jae/Y) mutants and their wild-type male siblings that served as negative controls. In positive control mice carrying a maternally inherited Ube3a deletion, Ube3a sense transcript and protein levels were drastically reduced. Our data contrast with two recent reports of substantially decreased Ube3a expression in brain tissues of MeCP2-deficient mice. We, therefore, challenge the conclusion that decreased UBE3A/Ube3a expression contributes to the pathophysiology of RTT.
Hum Mol Genet 2006 Jul 15
PMID:Ube3a expression is not altered in Mecp2 mutant mice. 1675 45

Rett syndrome (RTT) is a severe neurological disorder caused by mutations in the X-linked MECP2 gene, which encodes a methyl-CpG binding transcriptional repressor. Using the Mecp2-null mouse (an animal model for RTT) and differential display, we found that mice with neurological symptoms overexpress the nuclear gene for ubiquinol-cytochrome c reductase core protein 1 (Uqcrc1). Chromatin immunoprecipitation demonstrated that MeCP2 interacts with the Uqcrc1 promoter. Uqcrc1 encodes a subunit of mitochondrial respiratory complex III, and isolated mitochondria from the Mecp2-null brain showed elevated respiration rates associated with respiratory complex III and an overall reduction in coupling. A causal link between Uqcrc1 gene overexpression and enhanced complex III activity was established in neuroblastoma cells. Our findings raise the possibility that mitochondrial dysfunction contributes to pathology of the Mecp2-null mouse and may contribute to the long-known resemblance between Rett syndrome and certain mitochondrial disorders.
Mol Cell Biol 2006 Jul
PMID:Gene expression analysis exposes mitochondrial abnormalities in a mouse model of Rett syndrome. 1678 89

Impaired local protein translation at postsynaptic sites has been hypothesized to be the cause of several neurological disorders such as fragile X syndrome, neurofibromatosis-1, Rett syndrome, and other syndromic and non-specific forms of mental retardation. Identification of which mRNAs are present in dendrites and the identification of the molecular pathways that they promote will be imperative to the understanding of the neuropathology of these diseases. Since mouse models are the most widely used animal models of human diseases we developed a cell culture based technique to isolate mRNAs from mouse neurites.
J Mol Histol 2006 Jan
PMID:Isolation of mouse neuritic mRNAs. 1682 Oct 94

A tapetum-specific gene, RTS, has been isolated by differential screening of a cDNA library from rice panicles. RTS is a unique gene in the rice genome. RNA blot analysis and in situ hybridization indicates that this gene is predominantly expressed in the anther's tapetum during meiosis and disappears before anthesis. RTS has no introns and encodes a putative polypeptide of 94 amino acids with a hydrophobic N-terminal region. The nucleotide and deduced amino acid sequence of the gene do not show significant homology to any known sequences. However, a sequence in the promoter region, GAATTTGTTA, differs only by one or two nucleotides from one of the conserved motifs in the promoter region of two pollen-specific genes of tomato. Several other sequence motifs found in other anther-specific promoters were also identified in the promoter of the RTS gene. Transgenic and antisense RNA approaches revealed that RTS gene is required for male fertility in rice. The promoter region of RTS, when fused to the Bacillus amyloliquefaciens ribonuclease gene, barnase, or the antisense of the RTS gene, is able to drive tissue-specific expression of both genes in rice, creeping bentgrass (Agrostis stolonifera L.) and Arabidopsis, conferring male sterility to the transgenic plants. Light and near-infrared confocal microscopy of cross-sections through developing flowers of male-sterile transgenics shows that tissue-specific expression of barnase or the antisense RTS genes interrupts tapetal development, resulting in deformed non-viable pollen. These results demonstrate a critical role of the RTS gene in pollen development in rice and the versatile application of the RTS gene promoter in directing anther-specific gene expression in both monocotyledonous and dicotyledonous plants, pointing to a potential for exploiting this gene and its promoter for engineering male sterility for hybrid production of various plant species.
Plant Mol Biol 2006 Oct
PMID:RTS, a rice anther-specific gene is required for male fertility and its promoter sequence directs tissue-specific gene expression in different plant species. 1689 70

The autism spectrum disorders (ASD) comprise a complex group of behaviorally related disorders that are primarily genetic in origin. Involvement of epigenetic regulatory mechanisms in the pathogenesis of ASD has been suggested by the occurrence of ASD in patients with disorders arising from epigenetic mutations (fragile X syndrome) or that involve key epigenetic regulatory factors (Rett syndrome). Moreover, the most common recurrent cytogenetic abnormalities in ASD involve maternally derived duplications of the imprinted domain on chromosome 15q11-13. Thus, parent of origin effects on sharing and linkage to imprinted regions on chromosomes 15q and 7q suggest that these regions warrant specific examination from an epigenetic perspective, particularly because epigenetic modifications do not change the primary genomic sequence, allowing risk epialleles to evade detection using standard screening strategies. This review examines the potential role of epigenetic factors in the etiology of ASD.
Hum Mol Genet 2006 Oct 15
PMID:Epigenetics of autism spectrum disorders. 1698 77

Mutations of the methylated DNA binding protein MeCP2, a multifunctional protein that is thought to transmit epigenetic information encoded as methylated CpG dinucleotides to the transcriptional machinery, give rise to the debilitating neurodevelopmental disease Rett syndrome (RTT). In this in vitro study, the methylation-dependent and -independent interactions of wild-type and mutant human MeCP2 with defined DNA and chromatin substrates were investigated. A combination of electrophoretic mobility shift assays and visualization by electron microscopy made it possible to understand the different conformational changes underlying the gel shifts. MeCP2 is shown to have, in addition to its well-established methylated DNA binding domain, a methylation-independent DNA binding site (or sites) in the first 294 residues, while the C-terminal portion of MeCP2 (residues 295 to 486) contains one or more essential chromatin interaction regions. All of the RTT-inducing mutants tested were quantitatively bound to chromatin under our conditions, but those that tend to be associated with the more severe RTT symptoms failed to induce the extensive compaction observed with wild-type MeCP2. Two modes of MeCP2-driven compaction were observed, one promoting nucleosome clustering and the other forming DNA-MeCP2-DNA complexes. MeCP2 binding to DNA and chromatin involves a number of different molecular interactions, some of which result in compaction and oligomerization. The multifunctional roles of MeCP2 may be reflected in these different interactions.
Mol Cell Biol 2007 Feb
PMID:Multiple modes of interaction between the methylated DNA binding protein MeCP2 and chromatin. 1710 71

Analysis of cDNAs from Macrovipera lebetina transmediterranea (Mlt) and Echis ocellatus (Eo) venom gland libraries encoding disintegrins argued strongly for a common ancestry of the messengers of short disintegrins and those for precursors of dimeric disintegrin chains. We now report the sequence analysis of disintegrin-coding genes from these two vipers. Genomic DNAs for dimeric disintegrin subunits Ml_G1 and Ml_G2 (Mlt) and Eo_D3 (Eo) contain single 1-kb introns exhibiting the 5'-GTAAG (donor)/3'-AG (acceptor) consensus intron splicing signature. On the other hand, the short RTS-disintegrins Ml_G3 (Mlt) and Eo_RTS (Eo) and the short RGD-disintegrin ocellatusin (Eo) are transcribed from intronless genomic DNA sequences, indicating that the evolutionary pathway leading to the emergence of short disintegrins involved the removal of all intronic sequences. The insertion position of the intron within Ml_G1, Ml_G2, and Eo_D3 is conserved in the genes for vertebrate ADAM (A disintegrin and metalloproteinase) protein disintegrin-like domains and within the gene for the medium-size snake disintegrins halystatins 2 and 3. However, a comparative analysis of currently available disintegrin(-like) genes outlines the view that a minimization of both the gene organization and the protein structure underlies the evolution of the snake venom disintegrin family.
J Mol Evol 2007 Feb
PMID:Loss of introns along the evolutionary diversification pathway of snake venom disintegrins evidenced by sequence analysis of genomic DNA from Macrovipera lebetina transmediterranea and Echis ocellatus. 1717 90

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder linked to heterozygous de novo mutations in the MECP2 gene. MECP2 encodes methyl-CpG-binding protein 2 (MeCP2), which represses gene transcription by binding to 5-methylcytosine residues in symmetrically positioned CpG dinucleotides. Direct MeCP2 targets underlying RTT pathogenesis remain largely unknown. Here, we report that FXYD1, which encodes a transmembrane modulator of Na(+), K(+) -ATPase activity, is elevated in frontal cortex (FC) neurons of RTT patients and Mecp2-null mice. Increasing neuronal FXDY1 expression is sufficient to reduce dendritic arborization and spine formation, hallmarks of RTT neuropathology. Mecp2-null mouse cortical neurons have diminished Na(+),K(+)-ATPase activity, suggesting that aberrant FXYD1 expression contributes to abnormal neuronal activity in RTT. MeCP2 represses Fxyd1 transcription through direct interactions with sequences in the Fxyd1 promoter that are methylated in FC neurons. FXYD1 is therefore a MeCP2 target gene whose de-repression may directly contribute to RTT neuronal pathogenesis.
Hum Mol Genet 2007 Mar 15
PMID:FXYD1 is an MeCP2 target gene overexpressed in the brains of Rett syndrome patients and Mecp2-null mice. 1730 81

Forty years ago, researchers first demonstrated that immunization with irradiated sporozoites could protect against malaria infection, providing the impetus for the development of a malaria vaccine. Twenty five years ago, the circumsporozoite protein (CSP), a sporozoite surface antigen that is required to establish infection, became the first Plasmodium falciparum gene to be cloned, and a vaccine based on this antigen appeared imminent. However, today we are still without a highly effective malaria vaccine, despite considerable progress achieved during many years of research and development. This review highlights the most recent test-of-concept studies involving subunit vaccines; to illustrate this field of research, five antigens--CSP, TRAP/SSP2, LSA1, MSP1 and AMA1--are discussed. These antigens have all entered clinical trials evaluating efficacy against experimental sporozoite challenge (phase IIa) and/or exposure to natural infection (phase IIb). Challenges facing the development of subunit-based vaccines are discussed, and strategies for improving their efficacy above that observed with the current leading vaccine candidate, RTS,S, are described. In addition, recent progress in the development of whole-organism vaccines is presented.
Curr Opin Mol Ther 2007 Feb
PMID:Malaria vaccines: are we getting closer? 1733 Mar 98


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