Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
 19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ALS genes of Candida albicans encode a family of cell-surface glycoproteins that are composed of an N-terminal domain, a central domain of a tandemly repeated motif, and a relatively variable C-terminal domain. Although several ALS genes have been characterized, more ALS-like sequences are present in the C. albicans genome. Two short DNA sequences with similarity to the 5' domains of known ALS genes were detected among data from the C. albicans genome sequencing project. Probes developed from unique regions of these sequences were used to screen a genomic library from which two full-length genes, designated ALS6 and ALS7, were cloned. ALS6 and ALS7 encode features similar to other genes in the ALS family and map to chromosome 3, a chromosome previously not known to encode ALS sequences. ALS6 and ALS7 are present in all C. albicans strains examined. Additional analysis suggested that some C. albicans strains have another ALS gene with a 5' domain similar to that of ALS6. Characterization of ALS7 revealed a novel tandemly repeated sequence within the C-terminal domain. Unlike other ALS family tandem repeats, the newly characterized ALS7 repeat does not appear to define additional genes in the ALS family. However, our data and information from the C. albicans genome sequencing project suggest that there are additional ALS genes remaining to be characterized.
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PMID:The ALS6 and ALS7 genes of Candida albicans. 1086 7

The ALS (agglutinin-like sequence) gene family encodes proteins that play a role in adherence of the yeast Candida albicans to endothelial and epithelial cells. The proteins are proposed as virulence factors for this important fungal pathogen of humans. We analyzed 66 C. albicans strains, representing a worldwide collection of 266 infection-causing isolates, and discovered 60 alleles of the ALS7 open reading frame (ORF). Differences between alleles were largely caused by rearrangements of repeat elements in the so-called tandem repeat domain (21 different types occurred) and the VASES region (19 different types). C. albicans is diploid, and combinations of ALS7 alleles generated 49 different genotypes. ALS7 expression was detected in samples isolated directly from five oral candidosis patients. ORFs in the opposite direction contained within the ALS7 ORF were also transcribed in all strains tested. Isolates representing a more pathogenic general-purpose genotype (GPG) cluster of strains tended to have more tandem repeats than other strains. Two types of VASES regions were largely exclusive to GPG strains; the remaining types were largely exclusive to noncluster strains. Our results provide evidence that ALS7 is a hypermutable contingency locus and important for the success of C. albicans as an opportunistic pathogen of humans.
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PMID:Sixty alleles of the ALS7 open reading frame in Candida albicans: ALS7 is a hypermutable contingency locus. 1295 72

The ALS gene family of Candida albicans consists of eight genes (ALS1 to ALS7 and ALS9) that encode cell-wall glycoproteins involved in adhesion to host surfaces. Considerable allelic sequence variability has been documented for regions of ALS genes encoding repeated sequences. Although regions of ALS genes encoding non-repeated sequences tend to be more conserved, some sequence divergence has been noted, particularly for alleles of ALS5. Data from the C. albicans genome sequencing project provided the first indication that strain SC5314 encoded two divergent ALS9-like sequences and that three of the ALS genes (ALS5, ALS1 and ALS9) were contiguous on chromosome 6. Data from PCR analysis and construction of both single and double deletion mutants indicated that the divergent sequences were alleles of ALS9, and located downstream of ALS5 and ALS1. Sequences within the 5' domain of ALS9-1 and ALS9-2 varied by 11 %. Within the 3' domain of each allele, extra nucleotides were present in two regions of ALS9-2, designated Variable Block 1 (VB1) and Variable Block 2 (VB2). Analysis of strains from the five major C. albicans genetic clades showed that both ALS9 alleles are widespread among these strains, that the sequences of ALS9-1 and ALS9-2 are conserved among diverse strains and that recombinant ALS9 alleles have been generated during C. albicans evolution. Phylogenetic analysis showed that, although divergent in sequence, ALS9 alleles are more similar to each other than to any other ALS genes. The degree of sequence divergence for ALS9 greatly exceeds that observed previously for other ALS genes and may result in functional differences for the proteins encoded by the two alleles.
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PMID:Allelic variation in the contiguous loci encoding Candida albicans ALS5, ALS1 and ALS9. 1452 27

An RT-PCR assay was developed to analyse expression patterns of genes in the Candida albicans ALS (agglutinin-like sequence) family. Inoculation of a reconstituted human buccal epithelium (RHE) model of mucocutaneous candidiasis with strain SC5314 showed destruction of the epithelial layer by C. albicans and also formation of an upper fungal layer that had characteristics similar to a biofilm. RT-PCR analysis of total RNA samples extracted from C. albicans-inoculated buccal RHE showed that ALS1, ALS2, ALS3, ALS4, ALS5 and ALS9 were consistently detected over time as destruction of the RHE progressed. Detection of transcripts from ALS7, and particularly from ALS6, was more sporadic, but not associated with a strictly temporal pattern. The expression pattern of ALS genes in C. albicans cultures used to inoculate the RHE was similar to that observed in the RHE model, suggesting that contact of C. albicans with buccal RHE does little to alter ALS gene expression. RT-PCR analysis of RNA samples extracted from model denture and catheter biofilms showed similar gene expression patterns to the buccal RHE specimens. Results from the RT-PCR analysis of biofilm RNA specimens were consistent between various C. albicans strains during biofilm development and were comparable to gene expression patterns in planktonic cells. The RT-PCR assay described here will be useful for analysis of human clinical specimens and samples from other disease models. The method will provide further insight into the role of ALS genes and their encoded proteins in the diverse interactions between C. albicans and its host.
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PMID:RT-PCR detection of Candida albicans ALS gene expression in the reconstituted human epithelium (RHE) model of oral candidiasis and in model biofilms. 1476 4

The gene encoding yeast-enhanced green fluorescent protein (GFP) was placed under control of ALS gene promoters in Candida albicans. The PALS-GFP reporter strains were validated using various techniques including a new real-time RT-PCR assay to quantify ALS gene expression. The PALS-GFP reporter strains were grown in media that promoted yeast or germ tube forms, and the resulting fluorescence was measured by flow cytometry. In addition to results that indicate differences in ALS gene expression due to growth medium, growth stage and developmental programme, new data show large differences in transcriptional level among the ALS genes. Expression of ALS1 was associated with transfer of the PALS1-GFP strain to fresh growth medium. ALS3 expression increased markedly when germ tubes were visible microscopically and ALS7 expression exhibited a transient peak between 2 and 3 h following inoculation into fresh YPD medium. Transcription from the ALS1 and ALS3 promoters was strongest among those tested and contrasted markedly with the weaker promoter strength at the ALS5, ALS6, ALS7 and ALS9 loci. These weaker transcriptional responses were also observed using real-time RT-PCR measurements on wild-type C. albicans cells. Assuming a positive correlation between transcriptional level and protein production, these results suggest that some Als proteins are abundant on the C. albicans cell surface while others are produced at a much lower level.
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PMID:Construction and real-time RT-PCR validation of Candida albicans PALS-GFP reporter strains and their use in flow cytometry analysis of ALS gene expression in budding and filamenting cells. 1581 74

ALS gene expression was studied in the hyposalivatory rat model of oral candidiasis and in clinical specimens collected from HIV-positive patients to assess similarities in expression patterns between the model system and clinical isolates. Two Candida albicans strains, SC5314 and OY-2-76, were used in the rat model system and infection progressed for 3 or 5 days. The strains produced similar oral lesions at 3 days. At 5 days, strain OY-2-76 produced more superficial lesions containing relatively more yeast forms compared to invasive hyphal forms observed for strain SC5314. For all infections, the most severe lesions were observed on the tongue and gingiva overlying the mandible. ALS transcripts were easier to detect by RT-PCR later in infection and under other conditions where more fungal cells were present. Expression of ALS1, ALS2, ALS3 and ALS4 was observed in rats infected for 3 days with ALS5 and ALS9 transcripts detected after 5 days of infection. Expression of ALS6 was observed in a single specimen from a 5-day infection while ALS7 transcript was never found. Expression of all ALS genes was observed in oral clinical material collected from HIV-positive patients although ALS6 and ALS7 transcripts required an extra PCR amplification step to be detected. Overall, the patterns of ALS gene expression were similar between the rat model and human clinical specimens, suggesting that the model would be useful for studying the phenotype of al delta/al delta mutant strains.
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PMID:RT-PCR analysis of Candida albicans ALS gene expression in a hyposalivatory rat model of oral candidiasis and in HIV-positive human patients. 1651 12

Previously we observed that infection of HEp2 epithelial cells with Candida albicans results in HEp2 cell actin rearrangement as well as reduced membrane ruffling and motility and that supernatants of a C. albicans culture (Candida metabolite) caused the same changes. In this study, we used microarray analysis to determine changes in gene transcription of C. albicans following infection of HEp2 cells compared to control cultures grown in the absence of HEp2 cells. We observed 201 genes whose regulation was increased at least 2-fold following a 3 h incubation with HEp2 cells as well as 87 genes that are down-regulated. Among the up-regulated genes were ALS2 and ALS5 both of which encode proteins that provide an adherence function for C. albicans. To confirm the changes in ALS transcription, we measured by RT-PCR ALS1-9 at 1 h intervals for a total of 4 h. After 1 h of infection, several of the ALS genes were up-regulated compared to C. albicans grown alone. At 2-4 h, an increase in most of the ALS genes was observed in both infected and control cultures. ALS7 transcription was observed only at 3-4 h, but transcription was similar in both infected and control cultures. By RT-PCR, ALS2 and 5, similar to the microarray data, were significantly increased in infected cells at 3 h. Our results show that gene transcription following the adherence of C. albicans to HEp2 cells includes the up-regulation of genes encoding members of a family of known host recognition adhesins that may be critical to successful colonization and invasion of the organism.
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PMID:Gene transcription studies of Candida albicans following infection of HEp2 epithelial cells. 1677 26

The Candida albicans ALS (agglutinin-like sequence) family includes eight genes (ALS1 to ALS7, and ALS9) that share a common general organization, consisting of a relatively conserved 5' domain, a central domain of tandemly repeated sequence units, and a 3' domain of relatively variable length and sequence. To test the hypothesis that the cell-surface glycoproteins encoded by the ALS genes mediate contact between the fungal cell and host surfaces, a set of C. albicans mutant strains was systematically constructed, each lacking one of the ALS sequences. Phenotypes of the mutant strains were evaluated, primarily using adhesion assays. ALS9 is unique within the ALS family due to extensive allelic sequence variation within the 5' domain that may result in functional differences between proteins encoded by ALS9-1 and ALS9-2. Deletion of ALS9 significantly reduces C. albicans adhesion to human vascular endothelial cell monolayers. The mutation was complemented by reintegration of a wild-type copy of ALS9-2, but not ALS9-1, suggesting allelic functional differences. Complementation of the mutation with a gene fusion between the 5' domain of ALS9-2 and the tandem repeats and 3' domain of ALS9-1 also restored wild-type adhesion levels. Analysis of the als9Delta/als9Delta mutant phenotype in other assays demonstrated no significant difference from a control strain for adhesion to buccal epithelial cells or laminin-coated plastic plates. The als9Delta/als9Delta mutant did not show significant differences from the control for adhesion to or destruction of cells in the reconstituted human epithelium (RHE) disease model, or for cell-wall defects, germ-tube formation or biofilm formation in a catheter model. Analysis of ALS9 allelic frequency in a collection of geographically diverse clinical isolates showed a distinct preference for ALS9-2 allelic sequences, within both the 5' and the 3' domain of the ALS9 coding region. These data suggest greater selective pressure to maintain the ALS9-2 allele in C. albicans isolates and imply its greater relative importance in host-pathogen interactions.
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PMID:Unequal contribution of ALS9 alleles to adhesion between Candida albicans and human vascular endothelial cells. 1760 78

A selection of 43 Candida albicans isolates, chosen to represent the four major strain clades of the species and also intraclade diversity, was screened for their virulence in the murine intravenous challenge model of C. albicans infection, for a range of properties measurable in vitro that might relate to virulence, and for the numbers of midrepeat sequences in genes of the ALS and HYR families. Heterozygosity at the mating type locus and low whole-cell acid phosphatase activity and growth rate at 40 degrees C were found to be significantly positively associated with the most virulent isolates. Acid phosphatase activity and growth in 2 M NaCl were statistically significant variables between clades by univariate analysis. Isolates in different clades also differed significantly in midrepeat sequence alleles of ALS2, ALS4, ALS6, ALS7, ALS9, HYR1, and HYR2. There was no association between the midrepeat alleles of any ALS or HYR gene and the virulence of isolates to mice. Genome-wide transcript profiles of 20 isolates (5 per clade) grown under two conditions showed considerable variation between individual isolates, but only a small number of genes showed statistically significant differential gene expression between clades. Analysis of the expression profiles by overall strain virulence revealed 18 open reading frames differing significantly between isolates of high, intermediate, and low virulence. Four of these genes encoded functions related to phosphate uptake and metabolism. This finding and the significant association between whole-cell acid phosphatase activity and virulence led us to disrupt PHO100, which encodes a predicted periplasmic acid phosphatase. The pho100Delta mutant was mildly but significantly attenuated in terms of survival curves in the mouse model. The study has extended the range of properties known to differ between C. albicans clades and suggests a possible but minor role of phosphate metabolism in the virulence of the species.
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PMID:Property differences among the four major Candida albicans strain clades. 1915 28

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive muscle weakness that reflects degeneration of motor neurons in the primary motor cortex, corticospinal tracts, brainstem, and spinal cord. Most ALS cases are sporadic, but about 5%-10% are familial. The majority of familial ALS (FALS) cases follow an autosomal dominant inheritance pattern, and include the following mutations: ALS1, Cu/Zn superoxide dismutase (SOD1); ALS3; ALS4, senataxin; ALS6, fused in sarcoma (FUS); ALS7; ALS8, vesicle-associated membrane protein; ALS9, angiogenin; ALS10, TAR DNA-binding protein (TARDBP); and ALS11/FIG4. Some of these gene mutations are rarely seen in sporadic ALS cases. ALS2/alsin and ALS5 show an autosomal recessive inheritance pattern. Recently, mutations in the gene encoding optineurin, earlier reported to be a causative gene for primary open-angle glaucoma, have also been found in patients with ALS. It has also been demonstrated that a mutation in the D-amino acid oxidase gene is associated with classic adult-onset FALS. However, these genetic defects occur in only about 20%-30% FLAS cases, while most genes causing FALS remain unknown.
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PMID:[Gene mutations in familial amyotrophic lateral sclerosis]. 2130 Oct 41


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