Adenovirus Type 40 Host Range in Tissue Culture: A Study of the E1B Region

Growth restriction in tissue culture is a distinct feature of the enteric adenoviruses and they differ in this respect from all other subgroups of human adenoviruses. Ad40 cannot be passaged on Hela cells or primary HEK cells, but will grow in cells expressing the E1 region or only the E1B region of Ad2 or Ad5. The work described here was aimed at understanding the basis for this growth restriction. In coinfection experiments Ad40 complements an Ad5 E1A mutant and is itself complemented by that mutant as well as Ad5 and Adl2 wild type and E1B 19K mutant viruses. Ad5 and Ad12 E1B 55K mutant viruses are complemented to some extent by Ad40, these mutants however do not complement Ad40 growth on Hela cells. In order to study the E1B region of Ad40 a transcription map was determined from RNA produced at late times in infected KBa+b cells, using S1 nuclease, primer extension and PCR-cDNA analysis as well as Northern blotting. E1B transcripts corresponding to Ad2 14S, 22S and 9S mRNAs were identified but no 13S mRNA equivalent was detected, a pattern similar to that seen in the Adl2 transcription map. The coding potential for E1B 19K, 55K, and 15K proteins and for ppIX is retained in the Ad40 transcripts. In addition novel E1A-E1B cotranscript counterparts of the 14S and 22S mRNAs were identified. These contain the first 40 codons of the E1A first exon linked to a site 4-5nt downstream of the E1B cap site, retaining all the coding potential of the E1B mRNAs. No new open reading frames are created by the junction, and the E1A ORF terminates with one codon added after the junction. The E1A-E1B junction is unusual in that it does not conform to splice consensus sequences and thus may not be generated by a conventional splicing mechanism. Sequences around the 5' site of the junction bear a certain resemblance to spliced leader sequences utilized in trans-splicing in trypanosomes and nematodes. A timecourse of E1 transcription and DNA replication confirmed that. E1B transcripts are not detectable at early times in infection, but appear around the onset of DNA replication. The E1A-E1B cotranscripts are first seen at the same time as transcripts from the E1B promoter. Transcription from the Ad40 E1B promoter was analysed in transient transfection assays. Chloramphenicol acetyl transferase (CAT) activity was measured in cell extracts where the CAT gene was expressed under the control of the E1B promoter in the presence or absence of E1A products of Ad5 or Ad40. Expression from the Ad40 E1B promoter was not detectable even in the presence of Ad5 E1A, suggesting that unlike its Ad5 counterpart the Ad40 E1B promoter does not respond to E1A transactivation. This would account for the lack of early E1B gene expression in tissue culture. Moreover, this suggests that in the natural host cells of the virus E1B early gene products may not be needed, or alternatively, that early expression from the Ad40 E1B promoter is dependent on cellular factors present in the natural host cell, but absent in most common tissue culture cell lines. In this study Ad40 was shown to grow in an intestinal cell line, Int407, almost as well as in KB cells expressing the Ad2 E1 region. This provides a system in which to study Ad40 growth in tissue culture in the absence of complementing viral gene products

Association of neuregulin 1 with schizophrenia confirmed in a Scottish population

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldRecently, we identified neuregulin 1 (NRG1) as a susceptibility gene for schizophrenia in the Icelandic population, by a combined linkage and association approach. Here, we report the first study evaluating the relevance of NRG1 to schizophrenia in a population outside Iceland. Markers representing a core at-risk haplotype found in Icelanders at the 5' end of the NRG1 gene were genotyped in 609 unrelated Scottish patients and 618 unrelated Scottish control individuals. This haplotype consisted of five SNP markers and two microsatellites, which all appear to be in strong linkage disequilibrium. For the Scottish patients and control subjects, haplotype frequencies were estimated by maximum likelihood, using the expectation-maximization algorithm. The frequency of the seven-marker haplotype among the Scottish patients was significantly greater than that among the control subjects (10.2% vs. 5.9%, P=.00031). The estimated risk ratio was 1.8, which is in keeping with our report of unrelated Icelandic patients (2.1). Three of the seven markers in the haplotype gave single-point P values ranging from .000064 to .0021 for the allele contributing to the at-risk haplotype. This direct replication of haplotype association in a second population further implicates NRG1 as a factor that contributes to the etiology of schizophrenia

The T-381C SNP in BNP gene may be modestly associated with type 2 diabetes: an updated meta-analysis in 49 279 subjects

A recent study reported an association between the brain natriuretic peptide (BNP) promoter T-381C polymorphism (rs198389) and protection against type 2 diabetes (T2D). As replication in several studies is mandatory to confirm genetic results, we analyzed the T-381C polymorphism in seven independent case-control cohorts and in 291 T2D-enriched pedigrees totalling 39 557 subjects of European origin. A meta-analysis of the seven case-control studies (n = 39 040) showed a nominal protective effect [odds ratio (OR) = 0.86 (0.79-0.94), P = 0.0006] of the CC genotype on T2D risk, consistent with the previous study. By combining all available data (n = 49 279), we further confirmed a modest contribution of the BNP T-381C polymorphism for protection against T2D [OR = 0.86 (0.80-0.92), P = 1.4 × 10−5]. Potential confounders such as gender, age, obesity status or family history were tested in 4335 T2D and 4179 normoglycemic subjects and they had no influence on T2D risk. This study provides further evidence of a modest contribution of the BNP T-381C polymorphism in protection against T2D and illustrates the difficulty of unambiguously proving modest-sized associations even with large sample size

Common variants upstream of KDR encoding VEGFR2 and in TTC39B associate with endometriosis.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.We conducted a genome-wide association scan (GWAS) of endometriosis using 25.5 million sequence variants detected through whole-genome sequencing (WGS) of 8,453 Icelanders and imputed into 1,840 cases and 129,016 control women, followed by testing of associated variants in Danish samples. Here we report the discovery of a new endometriosis susceptibility locus on 4q12 (rs17773813[G], OR=1.28; P=3.8 × 10(-11)), upstream of KDR encoding vascular endothelial growth factor receptor 2 (VEGFR2). The variant correlates with disease severity (P=0.0046) when moderate/severe endometriosis cases are tested against minimal/mild cases. We further report association of rs519664[T] in TTC39B on 9p22 with endometriosis (P=4.8 × 10(-10); OR=1.29). The involvement of KDR in endometriosis risk highlights the importance of the VEGF pathway in the pathogenesis of the disease.e Danish National Research Foundation. Additional support for the DNBC has been obtained from the Danish Pharmacists’ Fund, the Egmont Foundation, the March of Dimes Birth Defects Foundation, the Augustinus Foundation and the Health Fund of the Danish Health Insurance Societies. B.F. is supported by an Oak Foundation fellowshi

Neuregulin 1 and susceptibility to schizophrenia

To access full text version of this article. Please click on the hyperlink "View/Open" at the bottom of this pageThe cause of schizophrenia is unknown, but it has a significant genetic component. Pharmacologic studies, studies of gene expression in man, and studies of mouse mutants suggest involvement of glutamate and dopamine neurotransmitter systems. However, so far, strong association has not been found between schizophrenia and variants of the genes encoding components of these systems. Here, we report the results of a genomewide scan of schizophrenia families in Iceland; these results support previous work, done in five populations, showing that schizophrenia maps to chromosome 8p. Extensive fine-mapping of the 8p locus and haplotype-association analysis, supplemented by a transmission/disequilibrium test, identifies neuregulin 1 (NRG1) as a candidate gene for schizophrenia. NRG1 is expressed at central nervous system synapses and has a clear role in the expression and activation of neurotransmitter receptors, including glutamate receptors. Mutant mice heterozygous for either NRG1 or its receptor, ErbB4, show a behavioral phenotype that overlaps with mouse models for schizophrenia. Furthermore, NRG1 hypomorphs have fewer functional NMDA receptors than wild-type mice. We also demonstrate that the behavioral phenotypes of the NRG1 hypomorphs are partially reversible with clozapine, an atypical antipsychotic drug used to treat schizophrenia

Refining the accuracy of validated target identification through coding variant fine-mapping in type 2 diabetes.

We aggregated coding variant data for 81,412 type 2 diabetes cases and 370,832 controls of diverse ancestry, identifying 40 coding variant association signals (P < 2.2 × 10-7); of these, 16 map outside known risk-associated loci. We make two important observations. First, only five of these signals are driven by low-frequency variants: even for these, effect sizes are modest (odds ratio ≤1.29). Second, when we used large-scale genome-wide association data to fine-map the associated variants in their regional context, accounting for the global enrichment of complex trait associations in coding sequence, compelling evidence for coding variant causality was obtained for only 16 signals. At 13 others, the associated coding variants clearly represent 'false leads' with potential to generate erroneous mechanistic inference. Coding variant associations offer a direct route to biological insight for complex diseases and identification of validated therapeutic targets; however, appropriate mechanistic inference requires careful specification of their causal contribution to disease predisposition

Variants in the fetal genome near FLT1 are associated with risk of preeclampsia.

Preeclampsia, which affects approximately 5% of pregnancies, is a leading cause of maternal and perinatal death. The causes of preeclampsia remain unclear, but there is evidence for inherited susceptibility. Genome-wide association studies (GWAS) have not identified maternal sequence variants of genome-wide significance that replicate in independent data sets. We report the first GWAS of offspring from preeclamptic pregnancies and discovery of the first genome-wide significant susceptibility locus (rs4769613; P = 5.4 × 10-11) in 4,380 cases and 310,238 controls. This locus is near the FLT1 gene encoding Fms-like tyrosine kinase 1, providing biological support, as a placental isoform of this protein (sFlt-1) is implicated in the pathology of preeclampsia. The association was strongest in offspring from pregnancies in which preeclampsia developed during late gestation and offspring birth weights exceeded the tenth centile. An additional nearby variant, rs12050029, associated with preeclampsia independently of rs4769613. The newly discovered locus may enhance understanding of the pathophysiology of preeclampsia and its subtypes