Showing papers by "Wellcome Trust Centre for Human Genetics published in 1999"
TL;DR: It is indicated that the interaction between HIF-1 and pVHL is iron dependent, and that it is necessary for the oxygen-dependent degradation of HIF α-subunits, which may underlie the angiogenic phenotype of VHL-associated tumours.
Abstract: Hypoxia-inducible factor-1 (HIF-1) has a key role in cellular responses to hypoxia, including the regulation of genes involved in energy metabolism, angiogenesis and apoptosis. The alpha subunits of HIF are rapidly degraded by the proteasome under normal conditions, but are stabilized by hypoxia. Cobaltous ions or iron chelators mimic hypoxia, indicating that the stimuli may interact through effects on a ferroprotein oxygen sensor. Here we demonstrate a critical role for the von Hippel-Lindau (VHL) tumour suppressor gene product pVHL in HIF-1 regulation. In VHL-defective cells, HIF alpha-subunits are constitutively stabilized and HIF-1 is activated. Re-expression of pVHL restored oxygen-dependent instability. pVHL and HIF alpha-subunits co-immunoprecipitate, and pVHL is present in the hypoxic HIF-1 DNA-binding complex. In cells exposed to iron chelation or cobaltous ions, HIF-1 is dissociated from pVHL. These findings indicate that the interaction between HIF-1 and pVHL is iron dependent, and that it is necessary for the oxygen-dependent degradation of HIF alpha-subunits. Thus, constitutive HIF-1 activation may underlie the angiogenic phenotype of VHL-associated tumours. The pVHL/HIF-1 interaction provides a new focus for understanding cellular oxygen sensing.
4,845 citations
TL;DR: It is demonstrated that mutations in ATP2A2 cause Darier disease and disclose a role for this pump in a Ca2+-signalling pathway regulating cell-to-cell adhesion and differentiation of the epidermis.
Abstract: Darier disease (DD) is an autosomal-dominant skin disorder characterized by loss of adhesion between epidermal cells (acantholysis) and abnormal keratinization. Recently we constructed a 2.4-Mb, P1-derived artificial chromosome contig spanning the DD candidate region on chromosome 12q23-24.1. After screening several genes that mapped to this region, we identified mutations in the ATP2A2 gene, which encodes the sarco/endoplasmic reticulum Ca2(+)-ATPase type 2 isoform (SERCA2) and is highly expressed in keratinocytes. Thirteen mutations were identified, including frameshift deletions, in-frame deletions or insertions, splice-site mutations and non-conservative missense mutations in functional domains. Our results demonstrate that mutations in ATP2A2 cause DD and disclose a role for this pump in a Ca(2+)-signalling pathway regulating cell-to-cell adhesion and differentiation of the epidermis.
667 citations
TL;DR: The identification of the environmental factors offers the real possibility of prevention of disease, and unravelling the genetics of allergic illnesses is likely to change their classification and treatment.
Abstract: The diseases of asthma, eczema and hay fever are typified by reactions to common allergens, which are mediated by immunoglobulin E. These allergic diseases are increasing in prevalence, and are now a major source of disability throughout the developed world. They are the result of complex interactions between largely unknown genetic and environmental mechanisms.The identification of the environmental factors offers the real possibility of prevention of disease, and unravelling the genetics of allergic illnesses is likely to change their classification and treatment. Early life seems particularly important, when the initiation of allergic disease may result from genetic and environmental modification of the immune interaction between mother and child.
370 citations
TL;DR: The results provide evidence that a specific mutation in Cx26 can impair epidermal differentiation, as well as inner ear function, and suggest that Vohwinkel's syndrome is a common mutation in classical VS.
Abstract: The multiplicity of functions served by intercellular gap junctions is reflected by the variety of phenotypes caused by mutations in the connexins of which they are composed. Mutations in the connexin26 (Cx26) gene (GJB2) at 13q11‐q13 are a major cause of autosomal recessive hearing loss (DFNB1), but have also been reported in autosomal dominant deafness (DFNA3). We now report a Cx26 mutation in three families with mutilating keratoderma and deafness [Vohwinkel’s syndrome (VS; MIM 124500), as originally described]. VS is characterized by papular and honeycomb keratoderma associated with constrictions of digits leading to autoamputation, distinctive starfish-like acral keratoses and moderate degrees of deafness. In a large British pedigree, we have mapped the defect to the Cx26 locus. All 10 affected members were heterozygous for a nonconservative mutation, D66H, in Cx26. The same mutation was found subsequently in affected individuals from two unrelated Spanish and Italian pedigrees segregating VS, suggesting that D66H in Cx26 is a common mutation in classical VS. This mutation occurs at a highly conserved residue in the first extracellular domain of the Cx26 molecule, and may exert its effects by interfering with assembly into connexons, docking with adjacent cells or gating properties of the gap junction. Our results provide evidence that a specific mutation in Cx26 can impair epidermal differentiation, as well as inner ear function.
314 citations
TL;DR: The findings indicate that the QTL affects both phonological and orthographic skills and is not specific to phoneme awareness, as has been previously suggested.
Abstract: Summary Recent application of nonparametric-linkage analysis to reading disability has implicated a putative quantitative-trait locus (QTL) on the short arm of chromosome 6. In the present study, we use QTL methods to evaluate linkage to the 6p25-21.3 region in a sample of 181 sib pairs from 82 nuclear families that were selected on the basis of a dyslexic proband. We have assessed linkage directly for several quantitative measures that should correlate with different components of the phenotype, rather than using a single composite measure or employing categorical definitions of subtypes. Our measures include the traditional IQ/reading discrepancy score, as well as tests of word recognition, irregular-word reading, and nonword reading. Pointwise analysis by means of sib-pair trait differences suggests the presence, in 6p21.3, of a QTL influencing multiple components of dyslexia, in particular the reading of irregular words ( P =.0016) and nonwords ( P =.0024). A complementary statistical approach involving estimation of variance components supports these findings (irregular words, P =.007; nonwords, P =.0004). Multipoint analyses place the QTL within the D6S422-D6S291 interval, with a peak around markers D6S276 and D6S105 consistently identified by approaches based on trait differences (irregular words, P =.00035; nonwords, P =.0035) and variance components (irregular words, P =.007; nonwords, P =.0038). Our findings indicate that the QTL affects both phonological and orthographic skills and is not specific to phoneme awareness, as has been previously suggested. Further studies will be necessary to obtain a more precise localization of this QTL, which may lead to the isolation of one of the genes involved in developmental dyslexia.
286 citations
TL;DR: The crystal structure at 2.2 Å resolution of a complex between TRAIL and the extracellular region of DR5 is reported, showing that TRAIL forms a central homotrimer around which three DR5 molecules bind.
Abstract: TRAIL, an apoptosis inducing ligand, has at least four cell surface receptors including the death receptor DR5. Here we report the crystal structure at 2.2 A resolution of a complex between TRAIL and the extracellular region of DR5. TRAIL forms a central homotrimer around which three DR5 molecules bind. Radical differences in the surface charge of the ligand, together with variation in the alignment of the two receptor domains confer specificity between members of these ligand and receptor families. The existence of a switch mechanism allowing variation in receptor domain alignment may mean that it is possible to engineer receptors with multiple specificities by exploiting contact positions unique to individual receptor-ligand pairs.
269 citations
TL;DR: The results indicate significant linkage across a distance of at least 5 cM for deficits in orthographic and phonological skills, confirming previous findings.
Abstract: Reading disability (RD), or dyslexia, is a complex cognitive disorder manifested by difficulties in learning to read, in otherwise normal individuals. Individuals with RD manifest deficits in several reading and language skills. Previous research has suggested the existence of a quantitative-trait locus (QTL) for RD on the short arm of chromosome 6. In the present study, RD subjects' performance in several measures of word recognition and component skills of orthographic coding, phonological decoding, and phoneme awareness were individually subjected to QTL analysis, with a new sample of 126 sib pairs, by means of a multipoint mapping method and eight informative DNA markers on chromosome 6 (D6S461, D6S276, D6S105, D6S306, D6S258, D6S439, D6S291, and D6S1019). The results indicate significant linkage across a distance of at least 5 cM for deficits in orthographic (LOD = 3.10) and phonological (LOD = 2.42) skills, confirming previous findings.
262 citations
TL;DR: A whole-genome radiation hybrid panel was used to construct a high-resolution map of the rat genome based on microsatellite and gene markers, described here for the first time, allowing the construction of detailed rat-mouse and rat-human comparative maps and illustrating the power of the RH approach for comparative mapping.
Abstract: A whole-genome radiation hybrid (RH) panel was used to construct a high-resolution map of the rat genome based on microsatellite and gene markers. These include 3,019 new microsatellite markers described here for the first time and 1,714 microsatellite markers with known genetic locations, allowing comparison and integration of maps from different sources. A robust RH framework map containing 1,030 positions ordered with odds of at least 1,000:1 has been defined as a tool for mapping these markers, and for future RH mapping in the rat. More than 500 genes which have been mapped in mouse and/or human were localized with respect to the rat RH framework, allowing the construction of detailed rat-mouse and rat-human comparative maps and illustrating the power of the RH approach for comparative mapping.
245 citations
TL;DR: It is found that severely anemic children with Plasmodium falciparum infection have low plasma TNF levels, in contrast to the high levels found in cerebral malaria, suggesting that severe malarial anemia and cerebral malaria are influenced by separate genetic factors situated near the TNF gene.
Abstract: Experimental evidence implicates tumor necrosis factor (TNF) in the pathogenesis of malarial anemia, but there are few data relating to this hypothesis. This study found that severely anemic children with Plasmodium falciparum infection have low plasma TNF levels, in contrast to the high levels found in cerebral malaria. A previous case-control study in The Gambia found cerebral malaria, but not severe malarial anemia, was associated with the TNF-308 A allele. This study found that in the same population, severe malarial anemia was associated with the TNF-238 A allele, with an odds ratio of 2.5 (P<.001) after stratification for HLA type. These findings suggest that severe malarial anemia and cerebral malaria are influenced by separate genetic factors situated near the TNF gene.
243 citations
TL;DR: This study suggests that the VDR polymorphism may influence susceptibility to some diseases by affecting the type and the strength of the host immune response.
Abstract: Host genetic factors including major histocompatibility complex (MHC) polymorphisms influence both susceptibility to leprosy per se and also to leprosy type. Non-MHC genes may play an important role, but such genes remain undefined. The influence of two non-MHC candidate genes was assessed in a case-control study of Bengali leprosy patients from Calcutta. Recent studies have implicated variation in the vitamin D receptor (VDR) gene in susceptibility to several diseases, including osteoporosis and pulmonary tuberculosis. In this population, homozygotes for the alternate alleles of the VDR polymorphism are associated, respectively, with lepromatous and tuberculoid leprosy. The NRAMP1 (natural resistance associated macrophage protein 1) gene may influence human mycobacterial disease susceptibility based on studies with the murine homologue Nramp1. However, no significant association was found between NRAMP1 and leprosy susceptibility. This study suggests that the VDR polymorphism may influence susceptibility to some diseases by affecting the type and the strength of the host immune response.
208 citations
TL;DR: The analysis, using three independent family sets, suggests the presence of an additional type I diabetes gene (or genes) in the MHC complex, useful for the analysis of other loci linked to common diseases.
Abstract: The human leukocyte antigen (HLA) complex, encompassing 3.5 Mb of DNA from the centromeric HLA-DPB2 locus to the telomeric HLA-F locus on chromosome 6p21, encodes a major part of the genetic predisposition to develop type 1 diabetes, designated "IDDM1." A primary role for allelic variation of the class II HLA-DRB1, HLA-DQA1, and HLA-DQB1 loci has been established. However, studies of animals and humans have indicated that other, unmapped, major histocompatibility complex (MHC)-linked genes are participating in IDDM1. The strong linkage disequilibrium between genes in this complex makes mapping a difficult task. In the present paper, we report on the approach we have devised to circumvent the confounding effects of disequilibrium between class II alleles and alleles at other MHC loci. We have scanned 12 Mb of the MHC and flanking chromosome regions with microsatellite polymorphisms and analyzed the transmission of these marker alleles to diabetic probands from parents who were homozygous for the alleles of the HLA-DRB1, HLA-DQA1, and HLA-DQB1 genes. Our analysis, using three independent family sets, suggests the presence of an additional type I diabetes gene (or genes). This approach is useful for the analysis of other loci linked to common diseases, to verify if a candidate polymorphism can explain all of the association of a region or if the association is due to two or more loci in linkage disequilibrium with each other.
TL;DR: No significant evidence of association or linkage was found at any of the markers tested, indicating that the 5-HTT and the GABRB3 genes are unlikely to play a major role in the aetiology of autism in the family data set.
Abstract: Previous studies have suggested that the serotonin transporter (5-HTT) gene and the gamma-aminobutyric acid receptor subunit beta3 (GABRB3) gene, or other genes in the 15q11-q13 region, are possibly involved in susceptibility to autism. To test this hypothesis we performed an association study on the collection of families from the International Molecular Genetic Study of Autism (IMGSA) Consortium, using the transmission disequilibrium test. Two polymorphisms in the 5-HTT gene (a functional insertion-deletion polymorphism in the promoter and a variable number tandem repeat in the second intron) were examined in 90 families comprising 174 affected individuals. Furthermore, seven microsatellite markers spanning the 15q11-q13 region were studied in 94 families with 182 affected individuals. No significant evidence of association or linkage was found at any of the markers tested, indicating that the 5-HTT and the GABRB3 genes are unlikely to play a major role in the aetiology of autism in our family data set.
TL;DR: A spectrum of ATP2A2 mutations in 19 families and six sporadic cases with Darier's disease supports the proposal that haploin-sufficiency is a common molecular mechanism for DD and suggests that additional factors are important contributors to the clinical phenotype.
Abstract: Darier's disease (DD) is an autosomal dominantly inherited skin disorder characterized by loss of adhesion between epidermal cells (acantholysis) and abnormal keratinization. Recently, we identified ATP2A2 encoding the sarco/endoplasmic reticulum Ca(2+)ATPase isoform 2 as the defective gene in DD. Now we report a spectrum of ATP2A2 mutations in 19 families and six sporadic cases with DD and investigate genotype-phenotype correlations. All 21 exons and flanking intron boundaries were amplified and screened for mutations by conformation-sensitive gel electrophoresis and direct sequencing. We identified 24 novel mutations that are scattered throughout the ATP2A2 gene. Two families shared an identical mutation on a common disease-associated haplotype, suggesting inheritance from a common ancestor. The majority of the mutations (54%; 13/24) led to a premature termination codon which further supports the proposal that haploin-sufficiency is a common molecular mechanism for DD. Thirty-eight per cent of mutations (9/24) result in non-conservative amino acid substitutions at highly conserved positions. Two mutations predict mutated polypeptides lacking or carrying additional amino acids. Marked inter- and intrafamilial phenotypic variability of the disease was observed. These results illustrate the considerable diversity of ATP2A2 mutations causing DD and suggest that additional factors are important contributors to the clinical phenotype.
TL;DR: In this article, the role of 23 candidate genes in the control of bone mineral density (BMD) by linkage studies in families of probands with osteoporosis (lumbar spine [LS] or femoral neck [FN] BMD T score < -2.5) and low BMD relative to an age and gender-matched cohort (Z score < 2.0).
Abstract: We have investigated the role of 23 candidate genes in the control of bone mineral density (BMD) by linkage studies in families of probands with osteoporosis (lumbar spine [LS] or femoral neck [FN] BMD T score < -2.5) and low BMD relative to an age- and gender-matched cohort (Z score < -2.0). One hundred and fifteen probands (35 male, 80 female) and 499 of their first- or second-degree relatives (223 males and 276 females) were recruited for the study. BMD was measured at the LS and FN using dual-energy X-ray absorptiometry and expressed as age- and gender-matched Z scores corrected for body mass index. The candidate genes studied were the androgen receptor, type I collagen A1 (COLIA1), COLIA2, COLIIA1, vitamin D receptor (VDR), colony-stimulating factor 1, calcium-sensing receptor, epidermal growth factor (EGF), estrogen receptor 1 (ESR1), fibrillin type 1, insulin-like growth factor 1, interleukin-1 alpha (IL-1α), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-11 (IL-11), osteopontin, parathyroid hormone (PTH), PTH-related peptide, PTH receptor type 1 (PTHR1), transforming growth factor-beta 1, and tumor necrosis factors alpha and beta. Sixty-four microsatellites lying close to or within these genes were investigated for linkage with BMD. Using the program MapMaker/Sibs there was suggestive evidence of linkage between BMD and PTHR1 (maximum LOD score obtained [MLS] 2.7-3.5). Moderate evidence of linkage was also observed with EGF (MLS 1.8), COLIA1 (MLS 1.7), COLIIA1/VDR (MLS 1.7), ESR1 (MLS 1.4), IL-1α (MLS 1.4), IL-4 (MLS 1.2), and IL-6 (MLS 1.2). Variance components analysis using the program ACT, correcting for proband-wise ascertainment, also showed evidence of linkage (p ≤0.05) at markers close to or within the candidate genes IL- 1α, PTHR1, IL-6, and COLIIA1/VDR. Further studies will be required to confirm these findings, to refine the location of gene responsible for the observed linkage, and to screen the candidate genes targeted at these loci for mutations.
TL;DR: This study suggests that the stomelysin-1 promoter polymorphism confers a genotype-specific response to medication in determining clinical event-free survival and the risk for symptom-driven repeat angioplasty.
Abstract: It has proved difficult to identify high-risk patients for atherosclerosis and to determine how they might respond to medication. Recently, a common promoter variant of the human stromelysin-1 gene has been reported, which has been shown to affect the transcription. We investigated whether this polymorphism had any impact on the risk of events, especially restenosis and progression of coronary artery disease and whether the effect was modulated by treatment with pravastatin. The stromelysin-1 genotype was determined for 496 men with coronary artery disease and cholesterol levels between 4.0 and 8.0 mmol/L, participating in the Regression Growth Evaluation Statin Study (REGRESS) study, a clinical trial assessing the effect of the lipid-lowering drug pravastatin on the progression of atherosclerosis. Patients in the placebo group with 5A6A or 6A6A genotypes had more clinical events than patients with the 5A5A genotype (26% and 12%, respectively, p = 0.03). In the pravastatin group, the risk of clinical events in patients with 5A6A or 6A6A genotypes was lower, compared with placebo, whereas it was unchanged in those with a 5A5A genotype (p value for interaction: 0.038). Also, the incidence of repeat angioplasty in the placebo group was greater in patients with the 6A6A or 5A6A genotypes, compared with 5A homozygotes (38% and 40%, respectively, vs 11%, p = 0.09). Again, treatment substantially reduced the incidence in heterozygotes and 6A homozygotes (0% and 15%, respectively), whereas it was unchanged in 5A homozygotes (28%, p for interaction: 0.002). These effects were independent of the effects of pravastatin on the lipid levels. Thus, this study suggests that the stomelysin-1 promoter polymorphism confers a genotype-specific response to medication in determining clinical event-free survival and the risk for symptom-driven repeat angioplasty. This variant may therefore act as a predictor, not only of disease progression, but also of response to therapy and risk of restenosis.
TL;DR: The data suggest that a female-specific susceptibility gene for idiopathic osteoarthritis-susceptibility loci is located on chromosome 11q, with evidence for linkage extending 12 cM proximal to this marker.
Abstract: We present a two-stage genomewide scan for osteoarthritis-susceptibility loci, using 481 families that each contain at least one affected sibling pair. The first stage, with 272 microsatellite markers and 297 families, involved a sparse map covering 23 chromosomes at intervals of approximately 15 cM. Sixteen markers that showed evidence of linkage at nominal P
TL;DR: Surface plasmon resonance is used to study the binding of soluble forms of KIR2DL1 and Kir2DL3 to several peptide-HLA-Cw7 complexes and indicates that KIR/peptide-MHC class I interactions have properties typical of other cell-cell recognition molecules, and they highlight the unusual nature of TCR/peptic-M HC recognition.
TL;DR: In the DNA/MVA regime, equally high CD8+ T cell responses and levels of protection are achieved using ten times less DNA when delivered with a gene gun compared to intramuscular injection.
TL;DR: Mutual 'interference' with the priming of human T-cell responses by a pair of naturally occurring variants of a malaria cytotoxic T- cell epitope is reported.
Abstract: Variation in epitopes of infectious pathogens inhibits various effector functions of T lymphocytes through antagonism of the T-cell receptor. However, a more powerful strategy for immune evasion would be to prevent the induction of T-cell responses. We report here mutual 'interference' with the priming of human T-cell responses by a pair of naturally occurring variants of a malaria cytotoxic T-cell epitope. Interference with priming also occurs in vivo for a murine malaria T-cell epitope. Reshaping of the T-cell repertoire by such immune interference during naive T-cell induction may provide a general mechanism for observed patterns of immunodominance and persistence by many polymorphic pathogens.
TL;DR: This work presents new insights into the interactions between classical MHC class I molecules and their cognate receptors on T cells through detailed analysis of the structures and functions of five nonclassical MHC-like molecules: HLA-DM (murine H2-M), Hla-E, HFE, ZAG and MIC-A.
TL;DR: This is the first example of dsRNA virus in which the structure of the polymerase complex has been determined without the assumption of icosahedral symmetry, and illustrates the symmetry mismatch which may occur at the sites of RNA packaging in other ds RNA viruses such as members of the Reoviridae.
TL;DR: Although CAV9 resembles coxsackie B viruses, several substitutions in the areas implicated in CBV receptor attachment suggest it may recognise a different receptor, and the structure along the fivefold axis provides new information on the uncoating mechanism of enteroviruses.
TL;DR: An episomal shuttle vector which can transfer large (>100 kb) human genomic DNA inserts back and forth between bacteria and human cells and which can be tracked in rapidly dividing human cells using a live cell assay is constructed.
Abstract: We have constructed an episomal shuttle vector which can transfer large (>100 kb) human genomic DNA inserts back and forth between bacteria and human cells and which can be tracked in rapidly dividing human cells using a live cell assay. The vector (p5170) is based on the F factor-derived bacterial artificial chromosome cloning vector used in Escherichia coli, with the addition of the family of repeats element from the Epstein-Barr virus (EBV) latent origin of replication. This element provides nuclear retention in cells expressing the EBV protein EBNA-1. We have subcloned a series of genomic DNA inserts into p5170 and transfected the constructs into an EBNA-1(+) human cell line. Episomal mitotic stability was quantitatively analysed using flow cytometry. The episomes were also tracked by time course photography of expanding colonies. A 117 kb episome was retained at approximately 2 copies/cell and could be shuttled unrearranged from the human cells into bacterial cells after 15 months of continuous cell growth. Furthermore, the episome could still be rescued from human cells cultured in the absence of selection for 198 days. Such a trackable E.coli /human cell line shuttle vector system capable of carrying >100 kb of genomic DNA in human cells could prove a valuable tool in gene expression studies.
TL;DR: It is suggested that rare alleles of the MUC3 gene may confer genetic predisposition to UC, and polymorphisms of variable number of tandem repeats (VNTRs) within this gene using DNAs obtained from 243 Japanese suggest this.
Abstract: Ulcerative colitis (UC), a common form of inflammatory bowel disease, is a multifactorial disorder with significant genetic influence. Recently, evidence of linkage on chromosome 7q near the intestinal mucin gene MUC3 was reported by an affected sib-pair analysis. Previous reports indicate a possible mucin abnormality in UC patients, but whether genetic differences in a specific mucin gene are associated with UC is unknown. Here we analysed polymorphisms of variable number of tandem repeats (VNTRs) within this gene using DNAs obtained from 243 Japanese (75 patients with UC and 168 controls), and to confirm the result we undertook a two-stage examination using 328 Caucasian samples (72 and 85 with UC in the first and second stages, respectively, and 171 controls). When the frequency of patients carrying one or two rare VNTR alleles was compared with that of controls, a significant increase was found first in Japanese patients (odds ratio 2.72, 95% CI 1.17-6.32, P = 0. 0308). In Caucasians, the odds ratio was 2.80 (95% CI 1.36-5.75, P = 0.0079) in the first stage, 2.43 (95% CI 1.20-4.92, P = 0.0196) in the second stage and 2.60 (95% CI 1.41-4.80, P = 0.0024) in total. The overall odds ratio was 2.64 (95% CI 1.60-4.33, P = 0.0001). This result suggests that rare alleles of the MUC3 gene may confer genetic predisposition to UC.
TL;DR: A di-leucine motif (L1487L1488) was essential for rapid internalisation of chimeric CD8 proteins and the full-length Menkes cDNA from the plasma membrane, and it is suggested that this motif mediates the retrieval of MNK from the Plasma membrane into the endocytic pathway, via the recycling endosomes, but is not sufficient to return the protein to the Golgi apparatus.
Abstract: The protein encoded by the Menkes disease gene (MNK) is localised to the Golgi apparatus and cycles between the trans-Golgi network and the plasma membrane in cultured cells on addition and removal of copper to the growth medium. This suggests that MNK protein contains active signals that are involved in the retention of the protein to the trans-Golgi network and retrieval of the protein from the plasma membrane. Previous studies have identified a signal involved in Golgi retention within transmembrane domain 3 of MNK. To identify a motif sufficient for retrieval of MNK from the plasma membrane, we analysed the cytoplasmic domain, downstream of transmembrane domain 7 and 8. Chimeric constructs containing this cytoplasmic domain fused to the reporter molecule CD8 localised the retrieval signal(s) to 62 amino acids at the C terminus. Further studies were performed on putative internalisation motifs, using site-directed mutagenesis, protein expression, chemical treatment and immunofluorescence. We observed that a di-leucine motif (L1487L1488) was essential for rapid internalisation of chimeric CD8 proteins and the full-length Menkes cDNA from the plasma membrane. We suggest that this motif mediates the retrieval of MNK from the plasma membrane into the endocytic pathway, via the recycling endosomes, but is not sufficient on its own to return the protein to the Golgi apparatus. These studies provide a basis with which to identify other motifs important in the sorting and delivery of MNK from the plasma membrane to the Golgi apparatus.
TL;DR: Results confirm that the enzymatic activity of p100 is distinct compared with that of p40/p46 and p69/p71, and synthesized preferentially dimeric 2′,5′-oligoadenylate molecules and displayed parameters for maximum enzyme activity similar to the natural p100.
TL;DR: A large number of genes appear to influence susceptibility to infectious pathogens and defining these can provide insights into pathogenic and protective mechanisms and identify new molecular targets for prophylactic and therapeutic interventions.
Abstract: Human genetic variation is a major determinant of susceptibility to many common infectious diseases. Malaria was the first disease to be studied extensively and many susceptibility and resistance loci have been identified. However, genes for other diseases such as HIV/AIDS and mycobacterial infections are now being identified using a variety of approaches. A large number of genes appear to influence susceptibility to infectious pathogens and defining these can provide insights into pathogenic and protective mechanisms and identify new molecular targets for prophylactic and therapeutic interventions. Immunogenetic associations with infectious diseases have considerable potential to guide immunomodulatory interventions and vaccine design.
TL;DR: No evidence of a parent-of-origin or a sex-specific effect is found in paternal and maternal meioses and transmissions to males and females separately, and transmission ratio distortion at the INS-IGF2 VNTR is found.
Abstract: defined as a statistically significant departure from mendelian transmission. So far, evidence of this in humans has been limited or controversial1–4, and the few established examples involve chromosome rearrangements in lower organisms5. The variable number of tandem repeat (VNTR) polymorphism 596 bp 5 ́ of the insulin gene (INS) regulates expression of both INS and the gene encoding insulinlike growth factor 2 (IGF2). The VNTR can be subdivided into two main allele sizes, class I and class III, in Europeans. Class III alleles are associated with reduced expression of INS and IGF2 in the pancreas and placenta6. As lower expression of VNTR class III-associated INS/IGF2 alleles early in fetal development may reduce the chances of survival in utero, the locus is considered a candidate for exhibiting TRD. Our initial study comprised 381 families with 1,128 children not ascertained by disease status (Table 1). We used the transmission/disequilibrium test7 (TDT) and found evidence for excess transmission of the class I allele (TRD=0.54; P = 0.04). To replicate this finding we analysed existing data for an independent set of 1,072 nuclear families with 1,079 children (Table 1) and obtained an identical TRD of 0.54 (P=0.02). Overall, the TRD of 0.54 was significant at P=0.002 (95% confidence limits=0.51
TL;DR: A heuristic approximation to the score distribution of gapped alignments in the logarithmic domain is presented and it is shown that gapped alignment behavior is essentially governed by a single parameter, alpha, depending on the penalty scheme and sequence composition.
Abstract: A heuristic approximation to the score distribution of gapped alignments in the logarithmic domain is presented. The method applies to comparisons between random, unrelated protein sequences, using...