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Karlberg, Olof
Publications (8 of 8) Show all publications
de Miranda, J. R., Hedman, H., Onorati, P., Stephan, J., Karlberg, O., Bylund, H. & Terenius, O. (2017). Characterization of a Novel RNA Virus Discovered in the Autumnal Moth Epirrita autumnata in Sweden. Viruses, 9(8), Article ID 214.
Open this publication in new window or tab >>Characterization of a Novel RNA Virus Discovered in the Autumnal Moth Epirrita autumnata in Sweden
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2017 (English)In: Viruses, ISSN 1999-4915, E-ISSN 1999-4915, Vol. 9, no 8, article id 214Article in journal (Refereed) Published
Abstract [en]

A novel, 10 kb RNA virus-tentatively named 'Abisko virus'-was discovered in the transcriptome data of a diseased autumnal moth (Epirrita autumnata) larva, as part of a search for the possible causes of the cyclical nature and mortality associated with geometrid moth dynamics and outbreaks in northern Fennoscandia. Abisko virus has a genome organization similar to that of the insect-infecting negeviruses, but phylogenetic and compositional bias analyses also reveal strong affiliations with plant-infecting viruses, such that both the primary host origin and taxonomic identity of the virus remain in doubt. In an extensive set of larval, pupal, and adult autumnal moth and winter moth (Operophtera brumata) outbreak samples, the virus was only detected in a few adult E. autumnata moths as well as the single larval transcriptome. The Abisko virus is therefore unlikely to be a factor in the Fennoscandia geometrid population dynamics.

Place, publisher, year, edition, pages
MDPI AG, 2017
Keywords
Epirrita autumnata, autumnal moth, Abisko virus, negevirus, Operophtera brumata, outbreak mortality
National Category
Microbiology
Identifiers
urn:nbn:se:uu:diva-335250 (URN)10.3390/v9080214 (DOI)000408742900016 ()
Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2017-12-04Bibliographically approved
Madrigal, I., Alvarez-Mora, M. I., Rosell, J., Rodríguez-Revenga, L., Karlberg, O., Sauer, S., . . . Mila, M. (2016). A novel splicing mutation in the IQSEC2 gene that modulates the phenotype severity in a family with intellectual disability.. European Journal of Human Genetics, 24(8), 1117-1123
Open this publication in new window or tab >>A novel splicing mutation in the IQSEC2 gene that modulates the phenotype severity in a family with intellectual disability.
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2016 (English)In: European Journal of Human Genetics, ISSN 1018-4813, E-ISSN 1476-5438, Vol. 24, no 8, p. 1117-1123Article in journal (Refereed) Published
Abstract [en]

The IQSEC2 gene is located on chromosome Xp11.22 and encodes a guanine nucleotide exchange factor for the ADP-ribosylation factor family of small GTPases. This gene is known to have a significant role in cytoskeletal organization, dendritic spine morphology and synaptic organization. Variants in IQSEC2 cause moderate to severe intellectual disability in males and a variable phenotype in females because this gene escapes from X-chromosome inactivation. Here we report on the first splicing variant in IQSEC2 (g.88032_88033del; NG_021296.1) that co-segregates in a family diagnosed with an X-linked form of ID. In a percentage of the cells, the variant activates an intraexonic splice acceptor site that abolishes 26 amino acids from the highly conserved PH domain of IQSEC2 and creates a premature stop codon 36 amino acids later in exon 13. Interestingly, the percentage of aberrant splicing seems to correlate with the severity of the disease in each patient. The impact of this variant in the target tissue is unknown, but we can hypothesize that these differences may be related to the amount of abnormal IQSEC2 transcript. To our knowledge, we are reporting a novel mechanism of IQSEC2 involvement in ID. Variants that affect splicing are related to many genetic diseases and the understanding of their role in disease expands potential opportunities for gene therapy. Modulation of aberrant splicing transcripts can become a potent therapeutic approach for many of these diseases.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-300957 (URN)10.1038/ejhg.2015.267 (DOI)000380390300008 ()26733290 (PubMedID)
External cooperation:
Funder
EU, FP7, Seventh Framework Programme, 262055
Available from: 2016-08-16 Created: 2016-08-16 Last updated: 2017-11-28Bibliographically approved
Tyden, E., Dahlberg, J., Karlberg, O. & Hoglund, J. (2014). Deep amplicon sequencing of preselected isolates of Parascaris equorum in beta-tubulin codons associated with benzimidazole resistance in other nematodes. Parasites & Vectors, 7, 410
Open this publication in new window or tab >>Deep amplicon sequencing of preselected isolates of Parascaris equorum in beta-tubulin codons associated with benzimidazole resistance in other nematodes
2014 (English)In: Parasites & Vectors, ISSN 1756-3305, E-ISSN 1756-3305, Vol. 7, p. 410-Article in journal (Refereed) Published
Abstract [en]

Background: The development of anthelmintic resistance (AR) to macrocyclic lactones in the equine roundworm Parascaris equorum has resulted in benzimidazoles now being the most widely used substance to control Parascaris infections. However, over-reliance on one drug class is a risk factor for the development of AR. Consequently, benzimidazole resistance is widespread in several veterinary parasites, where it is associated with single nucleotide polymorphisms (SNPs) in drug targets encoded by the beta-tubulin genes. The importance of these SNPs varies between different parasitic nematodes, but it has been hypothesised that they occur, at low allele frequencies, even in unselected populations. This study investigated whether these SNPs exist in the P. equorum population and tested the hypothesis that BZ resistance can develop from pre-existing SNPs in codons 167, 198 and 200 of the beta-tubulin isotype 1 and 2 genes, reported to be associated with AR in strongylids. The efficacy of the oral paste formula fenbendazole on 11 farms in Sweden was also assessed. Methods: Two isotype-specific primer pairs were designed, one on either side of the codon 167 and one on either side of codons 198 and 200. A pool of 100 000 larvae was sequenced using deep amplicon sequencing by Illumina HiSeq. Faecal egg count reduction test was used to assess the efficacy of fenbendazole. Results: No SNPs were observed in codons 167, 198 or 200 of the beta-tubulin isotype 1 or 2 genes of P. equorum, even though 100 000 larvae were sequenced. Faecal egg count reduction testing of fenbendazole showed that this anthelmintic was still 100% effective, meaning that the likelihood of finding high allele frequency of SNPs associated with benzimidazoles resistance in P. equorum was low. Unexpectedly, the allele frequencies observed in single worms were comparable to those in pooled samples. Conclusions: We concluded that fenbendazole does not exert selection pressure on the beta-tubulin genes of isotypes 1 and 2 in P. equorum. The fact that no pre-existing SNPs were found in codons 167, 198 and 200 in P. equorum also illustrates the difficulties in generalising about AR mechanisms between different taxonomic groups of nematodes.

Keywords
Parascaris equorum, Anthelmintic resistance, beta-tubulin, SNP, Fenbendazole, Illumina HiSeq
National Category
Medical Genetics
Identifiers
urn:nbn:se:uu:diva-233007 (URN)10.1186/1756-3305-7-410 (DOI)000341205100001 ()
Available from: 2014-10-09 Created: 2014-09-29 Last updated: 2018-01-11Bibliographically approved
Madrigal, I., Isabel Alvarez-Mora, M., Karlberg, O., Rodriguez-Revenga, L., Elurbe, D. M., Rabionet, R., . . . Mila, M. (2014). Efficient application of next-generation sequencing for the diagnosis of rare genetic syndromes. Journal of Clinical Pathology, 67(12), 1099-1103
Open this publication in new window or tab >>Efficient application of next-generation sequencing for the diagnosis of rare genetic syndromes
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2014 (English)In: Journal of Clinical Pathology, ISSN 0021-9746, E-ISSN 1472-4146, Vol. 67, no 12, p. 1099-1103Article in journal (Refereed) Published
Abstract [en]

Aims The causes of intellectual disability, which affects 1%-3% of the general population, are highly heterogeneous and the genetic defect remains unknown in around 40% of patients. The application of next-generation sequencing is changing the nature of biomedical diagnosis. This technology has quickly become the method of choice for searching for pathogenic mutations in rare uncharacterised genetic diseases. Methods Whole-exome sequencing was applied to a series of families affected with intellectual disability in order to identify variants underlying disease phenotypes. Results We present data of three families in which we identified the disease-causing mutations and which benefited from receiving a clinical diagnosis: Cornelia de Lange, Cohen syndrome and Dent-2 disease. The genetic heterogeneity and the variability in clinical presentation of these disorders could explain why these patients are difficult to diagnose. Conclusions The accessibility to next-generation sequencing allows clinicians to save much time and cost in identifying the aetiology of rare diseases. The presented cases are excellent examples that demonstrate the efficacy of next-generation sequencing in rare disease diagnosis.

National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-239749 (URN)10.1136/jclinpath-2014-202537 (DOI)000345281400015 ()25271213 (PubMedID)
Available from: 2014-12-31 Created: 2014-12-30 Last updated: 2018-01-11Bibliographically approved
Wang, C., Sandling, J. K., Hagberg, N., Berggren, O., Sigurdsson, S., Karlberg, O., . . . Syvänen, A.-C. (2013). Genome-wide profiling of target genes for the systemic lupus erythematosus-associated transcription factors IRF5 and STAT4. Annals of the Rheumatic Diseases, 72(1), 96-103
Open this publication in new window or tab >>Genome-wide profiling of target genes for the systemic lupus erythematosus-associated transcription factors IRF5 and STAT4
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2013 (English)In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 72, no 1, p. 96-103Article in journal (Refereed) Published
Abstract [en]

BACKGROUND:

The transcription factors interferon regulatory factor 5 (IRF5) and signal transducer and activator of transcription 4 (STAT4) are encoded by two of the strongest susceptibility genes for systemic lupus erythematosus (SLE).

OBJECTIVE:

To investigate the target genes and functional roles of IRF5 and STAT4 in human peripheral blood mononuclear cells (PBMCs).

METHODS:

Chromatin immunoprecipitation-sequencing (ChIP-seq) was performed in PBMCs stimulated to activate IRF5 and STAT4. The expression of the target genes of IRF5 and STAT4 was investigated in a publicly available dataset generated from PBMCs from patients with SLE and healthy controls. The genomic regions bound by the transcription complexes mediated by IRF5 and STAT4 were examined for transcription factor binding motifs and SLE-associated sequence variants.

RESULTS:

More than 7000 target genes for IRF5 and STAT4 were identified in stimulated PBMCs. These genes were enriched to functional pathways in the type I interferon system, and have key roles in the inflammatory response. The expression patterns of the target genes were characteristic for patients with SLE. The transcription factors high mobility group-I/Y, specificity protein 1, and paired box 4 may function cooperatively with IRF5 and STAT4 in transcriptional regulation. Eight of the target regions for IRF5 and STAT4 contain SLE-associated sequence variants.

CONCLUSIONS:

By participating in transcription complex with other co-factors, IRF5 and STAT4 harbour the potential of regulating a large number of target genes, which may contribute to their strong association with SLE.

Keywords
interferon regulatory factor 5, signal transducer and activator of transcription 4, systemic lupus erythematosus, ChIP-seq
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-179118 (URN)10.1136/annrheumdis-2012-201364 (DOI)000312407800016 ()22730365 (PubMedID)
Available from: 2012-08-08 Created: 2012-08-08 Last updated: 2017-12-07Bibliographically approved
't Hoen, P. A., Friedländer, M. R., Almlöf, J., Sammeth, M., Pulyakhina, I., Anvar, S. Y., . . . Lappalainen, T. (2013). Reproducibility of high-throughput mRNA and small RNA sequencing across laboratories. Nature Biotechnology, 31(11), 1015-1022
Open this publication in new window or tab >>Reproducibility of high-throughput mRNA and small RNA sequencing across laboratories
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2013 (English)In: Nature Biotechnology, ISSN 1087-0156, E-ISSN 1546-1696, Vol. 31, no 11, p. 1015-1022Article in journal (Refereed) Published
Abstract [en]

RNA sequencing is an increasingly popular technology for genome-wide analysis of transcript sequence and abundance. However, understanding of the sources of technical and interlaboratory variation is still limited. To address this, the GEUVADIS consortium sequenced mRNAs and small RNAs of lymphoblastoid cell lines of 465 individuals in seven sequencing centers, with a large number of replicates. The variation between laboratories appeared to be considerably smaller than the already limited biological variation. Laboratory effects were mainly seen in differences in insert size and GC content and could be adequately corrected for. In small-RNA sequencing, the microRNA (miRNA) content differed widely between samples owing to competitive sequencing of rRNA fragments. This did not affect relative quantification of miRNAs. We conclude that distributing RNA sequencing among different laboratories is feasible, given proper standardization and randomization procedures. We provide a set of quality measures and guidelines for assessing technical biases in RNA-seq data.

National Category
Genetics Bioinformatics and Systems Biology Medical Genetics
Research subject
Genetics
Identifiers
urn:nbn:se:uu:diva-207893 (URN)10.1038/nbt.2702 (DOI)000326921200023 ()24037425 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme
Available from: 2013-09-20 Created: 2013-09-20 Last updated: 2018-01-11Bibliographically approved
Lappalainen, T., Sammeth, M., Friedländer, M. R., 't Hoen, P. A., Monlong, J., Rivas, M. A., . . . Dermitzakis, E. T. (2013). Transcriptome and genome sequencing uncovers functional variation in humans. Nature, 501(7468), 506-511
Open this publication in new window or tab >>Transcriptome and genome sequencing uncovers functional variation in humans
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2013 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 501, no 7468, p. 506-511Article in journal (Refereed) Published
Abstract [en]

Genome sequencing projects are discovering millions of genetic variants in humans, and interpretation of their functional effects is essential for understanding the genetic basis of variation in human traits. Here we report sequencing and deep analysis of messenger RNA and microRNA from lymphoblastoid cell lines of 462 individuals from the 1000 Genomes Project-the first uniformly processed high-throughput RNA-sequencing data from multiple human populations with high-quality genome sequences. We discover extremely widespread genetic variation affecting the regulation of most genes, with transcript structure and expression level variation being equally common but genetically largely independent. Our characterization of causal regulatory variation sheds light on the cellular mechanisms of regulatory and loss-of-function variation, and allows us to infer putative causal variants for dozens of disease-associated loci. Altogether, this study provides a deep understanding of the cellular mechanisms of transcriptome variation and of the landscape of functional variants in the human genome.

National Category
Genetics Medical Genetics Bioinformatics and Systems Biology
Identifiers
urn:nbn:se:uu:diva-207901 (URN)10.1038/nature12531 (DOI)000324826300049 ()24037378 (PubMedID)
Available from: 2013-09-20 Created: 2013-09-20 Last updated: 2018-01-11Bibliographically approved
Nordlund, J., Kiialainen, A., Karlberg, O., Berglund, E. C., Göransson-Kultima, H., Sønderkær, M., . . . Syvänen, A.-C. (2012). Digital gene expression profiling of primary acute lymphoblastic leukemia cells. Leukemia, 26(6), 1218-1227
Open this publication in new window or tab >>Digital gene expression profiling of primary acute lymphoblastic leukemia cells
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2012 (English)In: Leukemia, ISSN 0887-6924, E-ISSN 1476-5551, Vol. 26, no 6, p. 1218-1227Article in journal (Refereed) Published
Abstract [en]

We determined the genome-wide digital gene expression (DGE) profiles of primary acute lymphoblastic leukemia (ALL) cells from 21 patients taking advantage of 'second-generation' sequencing technology. Patients included in this study represent four cytogenetically distinct subtypes of B-cell precursor (BCP) ALL and T-cell lineage ALL (T-ALL). The robustness of DGE combined with supervised classification by nearest shrunken centroids (NSC) was validated experimentally and by comparison with published expression data for large sets of ALL samples. Genes that were differentially expressed between BCP ALL subtypes were enriched to distinct signaling pathways with dic(9;20) enriched to TP53 signaling, t(9;22) to interferon signaling, as well as high hyperdiploidy and t(12;21) to apoptosis signaling. We also observed antisense tags expressed from the non-coding strand of ∼50% of annotated genes, many of which were expressed in a subtype-specific pattern. Antisense tags from 17 gene regions unambiguously discriminated between the BCP ALL and T-ALL subtypes, and antisense tags from 76 gene regions discriminated between the 4 BCP subtypes. We observed a significant overlap of gene regions with alternative polyadenylation and antisense transcription (P<1 × 10(-15)). Our study using DGE profiling provided new insights into the RNA expression patterns in ALL cells.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-168670 (URN)10.1038/leu.2011.358 (DOI)000305081000009 ()22173241 (PubMedID)
Available from: 2012-02-14 Created: 2012-02-14 Last updated: 2017-12-07Bibliographically approved
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