| 1. |
- Klevebring, Daniel, 1981-
(författare)
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On Transcriptome Sequencing
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is about the use of massive DNA sequencing to investigate the transcriptome. During recent decades, several studies have made it clear that the transcriptome comprises a more complex set of biochemical machinery than was previously believed. The majority of the genome can be expressed as transcripts; and overlapping and antisense transcription is widespread. New technologies for the interroga- tion of nucleic acids have made it possible to investigate such cellular phenomena in much greater detail than ever before. For each application, special requirements need to be met. The work presented in this thesis focuses on the transcrip- tome and the development of technology for its analysis. In paper I, we report our development of an automated approach for sample preparation. The procedure was benchmarked against a publicly available reference data set, and we note that our approach outperformed similar manual procedures in terms of reproducibility. In the work reported in papers II-IV, we used different massive sequencing technologies to investigate the transcriptome. In paper II we describe a concatemerization approach that increased throughput by 65% using 454 sequencing,and we identify classes of transcripts not previously described in Populus. Papers III and IV both report studies based on SOLiD sequencing. In the former, we investigated transcripts and proteins for 13% of the human gene and detected a massive overlap for the upper 50% transcriptional levels. In the work described in paper IV, we investigated transcription in non-genic regions of the genome and detected expression from a high number of previ- ously unknown loci.
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| 2. |
- Savolainen, Peter, et al.
(författare)
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mtDNA tandem repeats in domestic dogs and wolves : Mutation mechanism studied by analysis of the sequence of imperfect repeats
- 2000
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 17:4, s. 474-488
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Tidskriftsartikel (refereegranskat)abstract
- The mitochondrial (mt) DNA control region (CR) of dogs and wolves contains an array of imperfect 10 bp tandem repeats. This region was studied for 14 domestic dogs representing the four major phylogenetic groups of nonrepetitive CR and for 5 wolves. Three repeat types were found among these individuals, distributed so that different sequences of the repeat types were formed in different molecules. This enabled a detailed study of the arrays and of the mutation events that they undergo. Extensive heteroplasmy was observed in all individuals; 85 different array types were found in one individual, and the total number of types was estimated at 384. Among unrelated individuals, no identical molecules were found, indicating a high rate of evolution of the region. By performing a pedigree analysis, array types which had been inherited from mother to offspring and array types which were the result of somatic mutations, respectively, could be identified, showing that about 20% of the molecules within an individual had somatic mutations. By direct pairwise comparison of the mutated and the original array types, the physiognomy of the inserted or deleted elements (indels) and the approximate positions of the mutations could be determined. All mutations could be explained by replication slippage or point mutations. The majority of the indels were 1-5 repeats long, but deletions of up to 17 repeats were found. Mutations were found in all parts of the arrays, but at a higher frequency in the 5' end. Furthermore, the inherited array types within the mother-offspring pair were aligned and compared so that germ line mutations could be studied. The pattern of the germ line mutations was approximately the same as that of the somatic mutations.
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| 3. |
- Zhu, Y., et al.
(författare)
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Proteogenomics produces comprehensive and highly accurate protein-coding gene annotation in a complete genome assembly of Malassezia sympodialis
- 2017
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 45:5, s. 2629-2643
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Tidskriftsartikel (refereegranskat)abstract
- Complete and accurate genome assembly and annotation is a crucial foundation for comparative and functional genomics. Despite this, few complete eukaryotic genomes are available, and genome annotation remains a major challenge. Here, we present a complete genome assembly of the skin commensal yeast Malassezia sympodialis and demonstrate how proteogenomics can substantially improve gene annotation. Through long-read DNA sequencing, we obtained a gap-free genome assembly for M. sympodialis (ATCC 42132), comprising eight nuclear and one mitochondrial chromosome. We also sequenced and assembled four M. sympodialis clinical isolates, and showed their value for understanding Malassezia reproduction by confirming four alternative allele combinations at the two mating-type loci. Importantly, we demonstrated how proteomics data could be readily integrated with transcriptomics data in standard annotation tools. This increased the number of annotated protein-coding genes by 14% (from 3612 to 4113), compared to using transcriptomics evidence alone. Manual curation further increased the number of protein-coding genes by 9% (to 4493). All of these genes have RNA-seq evidence and 87% were confirmed by proteomics. The M. sympodialis genome assembly and annotation presented here is at a quality yet achieved only for a few eukaryotic organisms, and constitutes an important reference for future host-microbe interaction studies.
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| 4. |
- Hildebrandt, Franziska, 1994-, et al.
(författare)
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Spatial Transcriptomics to define transcriptional patterns of zonation and structural components in the mouse liver
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Reconstruction of heterogeneity through single cell transcriptional profiling has greatly advanced our understanding of the spatial liver transcriptome in recent years. However, global transcriptional differences across lobular units remain elusive in physical space. Here, we apply Spatial Transcriptomics to perform transcriptomic analysis across sectioned liver tissue. We confirm that the heterogeneity in this complex tissue is predominantly determined by lobular zonation. By introducing novel computational approaches, we enable transcriptional gradient measurements between tissue structures, including several lobules in a variety of orientations. Further, our data suggests the presence of previously transcriptionally uncharacterized structures within liver tissue, contributing to the overall spatial heterogeneity of the organ. This study demonstrates how comprehensive spatial transcriptomic technologies can be used to delineate extensive spatial gene expression patterns in the liver, indicating its future impact for studies of liver function, development and regeneration as well as its potential in pre-clinical and clinical pathology. Global transcriptional differences across lobular units in the liver remain unknown. Here the authors perform spatial transcriptomics of liver tissue to delineate transcriptional differences in physical space, confirm lobular zonation along transcriptional gradients and suggest the presence of previously uncharacterized structures within liver tissue.
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| 5. |
- Ståhl, Patrik, Dr., et al.
(författare)
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Visualization and analysis of gene expression in tissue sections by spatial transcriptomics
- 2016
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 353:6294, s. 78-82
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of the pattern of proteins or messenger RNAs (mRNAs) in histological tissue sections is a cornerstone in biomedical research and diagnostics. This typically involves the visualization of a few proteins or expressed genes at a time. We have devised a strategy, which we call "spatial transcriptomics," that allows visualization and quantitative analysis of the transcriptome with spatial resolution in individual tissue sections. By positioning histological sections on arrayed reverse transcription primers with unique positional barcodes, we demonstrate high-quality RNA-sequencing data with maintained two-dimensional positional information from the mouse brain and human breast cancer. Spatial transcriptomics provides quantitative gene expression data and visualization of the distribution of mRNAs within tissue sections and enables novel types of bioinformatics analyses, valuable in research and diagnostics.
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| 6. |
- Parigi, Sara M., et al.
(författare)
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The spatial transcriptomic landscape of the healing mouse intestine following damage
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- The colon is comprised of specialized cells that interact with each other to function, however, the molecular regionalization of the colon is incompletely understood. Here, the authors use spatial transcriptomics to generate a publicly available resource defining the transcriptomic regionalization of the colon during steady state and mucosal healing. The intestinal barrier is composed of a complex cell network defining highly compartmentalized and specialized structures. Here, we use spatial transcriptomics to define how the transcriptomic landscape is spatially organized in the steady state and healing murine colon. At steady state conditions, we demonstrate a previously unappreciated molecular regionalization of the colon, which dramatically changes during mucosal healing. Here, we identified spatially-organized transcriptional programs defining compartmentalized mucosal healing, and regions with dominant wired pathways. Furthermore, we showed that decreased p53 activation defined areas with increased presence of proliferating epithelial stem cells. Finally, we mapped transcriptomics modules associated with human diseases demonstrating the translational potential of our dataset. Overall, we provide a publicly available resource defining principles of transcriptomic regionalization of the colon during mucosal healing and a framework to develop and progress further hypotheses.
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| 7. |
- Lundeberg, Joakim
(författare)
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Spatially resolved gene expression
- 2022
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Ingår i: European Journal of Human Genetics. - : SPRINGERNATURE. - 1018-4813 .- 1476-5438. ; 30:SUPPL 1, s. 7-7
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Kvastad, Linda, et al.
(författare)
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The spatial RNA integrity number assay for in situ evaluation of transcriptome quality
- 2021
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Ingår i: Communications Biology. - : Springer Nature. - 2399-3642. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- The RNA integrity number (RIN) is a frequently used quality metric to assess the completeness of rRNA, as a proxy for the corresponding mRNA in a tissue. Current methods operate at bulk resolution and provide a single average estimate for the whole sample. Spatial transcriptomics technologies have emerged and shown their value by placing gene expression into a tissue context, resulting in transcriptional information from all tissue regions. Thus, the ability to estimate RNA quality in situ has become of utmost importance to overcome the limitation with a bulk rRNA measurement. Here we show a new tool, the spatial RNA integrity number (sRIN) assay, to assess the rRNA completeness in a tissue wide manner at cellular resolution. We demonstrate the use of sRIN to identify spatial variation in tissue quality prior to more comprehensive spatial transcriptomics workflows. Kvastad et al. develop the spatial RNA Integrity Number (sRIN) assay that evaluates the RNA integrity at cellular resolution. This method improves the resolution of a similar method called the RNA Integrity Number (RIN), demonstrating spatial variation in the quality of RNA samples.
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| 9. |
- Fernandez Navarro, Jose, et al.
(författare)
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Spatial Transcriptomics Reveals Genes Associated with Dysregulated Mitochondrial Functions and Stress Signaling in Alzheimer Disease
- 2020
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Ingår i: iScience. - : Elsevier Inc.. - 2589-0042. ; 23:10
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Tidskriftsartikel (refereegranskat)abstract
- Cellular Neuroscience; Omics; Transcriptomics Alzheimer disease (AD) is a devastating neurological disease associated with progressive loss of mental skills and cognitive and physical functions whose etiology is not completely understood. Here, our goal was to simultaneously uncover novel and known molecular targets in the structured layers of the hippocampus and olfactory bulbs that may contribute to early hippocampal synaptic deficits and olfactory dysfunction in AD mice. Spatially resolved transcriptomics was used to identify high-confidence genes that were differentially regulated in AD mice relative to controls. A diverse set of genes that modulate stress responses and transcription were predominant in both hippocampi and olfactory bulbs. Notably, we identify Bok, implicated in mitochondrial physiology and cell death, as a spatially downregulated gene in the hippocampus of mouse and human AD brains. In summary, we provide a rich resource of spatially differentially expressed genes, which may contribute to understanding AD pathology.
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| 10. |
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