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Publications

Publications by LIAAD

2017

QmihR: Pipeline for Quantification of Microbiome in Human RNA-seq

Authors
Cavadas, B; Ferreira, J; Camacho, R; Fonseca, NA; Pereira, L;

Publication
11th International Conference on Practical Applications of Computational Biology & Bioinformatics, PACBB 2017, Porto, Portugal, 21-23 June, 2017

Abstract
The huge amount of genomic and transcriptomic data obtained to characterize human diversity can also be exploited to indirectly gather information on the human microbiome. Here we present the pipeline QmihR designed to identify and quantify the abundance of known microbiome communities and to search for new/rare pathogenic species in RNA-seq datasets. We applied QmihR to 36 RNA-seq tumor tissue samples from Ukrainian gastric carcinoma patients available in TCGA, in order to characterize their microbiome and check for efficiency of the pipeline. The microbes present in the samples were in accordance to published data in other European datasets, and the independent BLAST evaluation of microbiome-aligned reads confirmed that the assigned species presented the highest BLAST match-hits. QmihR is available at GitHub (https://github.com/ Pereira-lab/QmihR). © Springer International Publishing AG 2017.

2017

The RNASeq-er API - a gateway to systematically updated analysis of public RNA-seq data

Authors
Petryszak, R; Fonseca, NA; Füllgrabe, A; Huerta, L; Keays, M; Tang, YA; Brazma, A;

Publication
Bioinformatics

Abstract
Motivation: The exponential growth of publicly available RNA-sequencing (RNA-Seq) data poses an increasing challenge to researchers wishing to discover, analyse and store such data, particularly those based in institutions with limited computational resources. EMBL-EBI is in an ideal position to address these challenges and to allow the scientific community easy access to not just raw, but also processed RNA-Seq data. We present a Web service to access the results of a systematically and continually updated standardized alignment as well as gene and exon expression quantification of all public bulk (and in the near future also single-cell) RNA-Seq runs in 264 species in European Nucleotide Archive, using Representational State Transfer. Results: The RNASeq-er API (Application Programming Interface) enables ontology-powered search for and retrieval of CRAM, bigwig and bedGraph files, gene and exon expression quantification matrices (Fragments Per Kilobase Of Exon Per Million Fragments Mapped, Transcripts Per Million, raw counts) as well as sample attributes annotated with ontology terms. To date over 270 00 RNA-Seq runs in nearly 10 000 studies (1PB of raw FASTQ data) in 264 species in ENA have been processed and made available via the API.

2017

Two independent modes of chromatin organization revealed by cohesin removal

Authors
Schwarzer, W; Abdennur, N; Goloborodko, A; Pekowska, A; Fudenberg, G; Loe Mie, Y; Fonseca, NA; Huber, W; Haering, CH; Mirny, L; Spitz, F;

Publication
Nature

Abstract
Imaging and chromosome conformation capture studies have revealed several layers of chromosome organization, including segregation into megabase-sized active and inactive compartments, and partitioning into sub-megabase domains (TADs). It remains unclear, however, how these layers of organization form, interact with one another and influence genome function. Here we show that deletion of the cohesin-loading factor Nipbl in mouse liver leads to a marked reorganization of chromosomal folding. TADs and associated Hi-C peaks vanish globally, even in the absence of transcriptional changes. By contrast, compartmental segregation is preserved and even reinforced. Strikingly, the disappearance of TADs unmasks a finer compartment structure that accurately reflects the underlying epigenetic landscape. These observations demonstrate that the three-dimensional organization of the genome results from the interplay of two independent mechanisms: cohesin-independent segregation of the genome into fine-scale compartments, defined by chromatin state; and cohesin-dependent formation of TADs, possibly by loop extrusion, which helps to guide distant enhancers to their target genes.

2017

Discovery and characterization of coding and non-coding driver mutations in more than 2,500 whole cancer genomes

Authors
Rheinbay, E; Nielsen, MM; Abascal, F; Tiao, G; Hornshøj, H; Hess, JM; Pedersen, RI; Feuerbach, L; Sabarinathan, R; Madsen, T; Kim, J; Mularoni, L; Shuai, S; Lanzós, A; Herrmann, C; Maruvka, YE; Shen, C; Amin, SB; Bertl, J; Dhingra, P; Diamanti, K; Gonzalez-Perez, A; Guo, Q; Haradhvala, NJ; Isaev, K; Juul, M; Komorowski, J; Kumar, S; Lee, D; Lochovsky, L; Liu, EM; Pich, O; Tamborero, D; Umer, HM; Uusküla-Reimand, L; Wadelius, C; Wadi, L; Zhang, J; Boroevich, KA; Carlevaro-Fita, J; Chakravarty, D; Chan, CW; Fonseca, NA; Hamilton, MP; Hong, C; Kahles, A; Kim, Y; Lehmann, K; Johnson, TA; Kahraman, A; Park, K; Saksena, G; Sieverling, L; Sinnott-Armstrong, NA; Campbell, PJ; Hobolth, A; Kellis, M; Lawrence, MS; Raphael, B; Rubin, MA; Sander, C; Stein, L; Stuart, J; Tsunoda, T; Wheeler, DA; Johnson, R; Reimand, J; Gerstein, MB; Khurana, E; López-Bigas, N; Martincorena, I; Pedersen, JS; Getz, G;

Publication

Abstract
AbstractDiscovery of cancer drivers has traditionally focused on the identification of protein-coding genes. Here we present a comprehensive analysis of putative cancer driver mutations in both protein-coding and non-coding genomic regions across >2,500 whole cancer genomes from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We developed a statistically rigorous strategy for combining significance levels from multiple driver discovery methods and demonstrate that the integrated results overcome limitations of individual methods. We combined this strategy with careful filtering and applied it to protein-coding genes, promoters, untranslated regions (UTRs), distal enhancers and non-coding RNAs. These analyses redefine the landscape of non-coding driver mutations in cancer genomes, confirming a few previously reported elements and raising doubts about others, while identifying novel candidate elements across 27 cancer types. Novel recurrent events were found in the promoters or 5’UTRs ofTP53, RFTN1, RNF34,andMTG2,in the 3’UTRs ofNFKBIZandTOB1,and in the non-coding RNARMRP.We provide evidence that the previously reported non-coding RNAsNEAT1andMALAT1may be subject to a localized mutational process. Perhaps the most striking finding is the relative paucity of point mutations driving cancer in non-coding genes and regulatory elements. Though we have limited power to discover infrequent non-coding drivers in individual cohorts, combined analysis of promoters of known cancer genes show little excess of mutations beyondTERT.

2017

Genomic basis for RNA alterations revealed by whole-genome analyses of 27 cancer types

Authors
Calabrese, C; Davidson, NR; Fonseca, NA; He, Y; Kahles, A; Lehmann, K; Liu, F; Shiraishi, Y; Soulette, CM; Urban, L; Demircioglu, D; Greger, L; Li, S; Liu, D; Perry, MD; Xiang, L; Zhang, F; Zhang, J; Bailey, P; Erkek, S; Hoadley, KA; Hou, Y; Kilpinen, H; Korbel, JO; Marin, MG; Markowski, J; Nandi, T; Pan-Hammarström, Q; Pedamallu, CS; Siebert, R; Stark, SG; Su, H; Tan, P; Waszak, SM; Yung, C; Zhu, S; Awadalla, P; Creighton, CJ; Meyerson, M; Ouellette, BF; Wu, K; Yang, H; Brazma, A; Brooks, AN; Göke, J; Rätsch, G; Schwarz, RF; Stegle, O; Zhang, Z;

Publication

Abstract
AbstractWe present the most comprehensive catalogue of cancer-associated gene alterations through characterization of tumor transcriptomes from 1,188 donors of the Pan-Cancer Analysis of Whole Genomes project. Using matched whole-genome sequencing data, we attributed RNA alterations to germline and somatic DNA alterations, revealing likely genetic mechanisms. We identified 444 associations of gene expression with somatic non-coding single-nucleotide variants. We found 1,872 splicing alterations associated with somatic mutation in intronic regions, including novel exonization events associated with Alu elements. Somatic copy number alterations were the major driver of total gene and allele-specific expression (ASE) variation. Additionally, 82% of gene fusions had structural variant support, including 75 of a novel class called “bridged” fusions, in which a third genomic location bridged two different genes. Globally, we observe transcriptomic alteration signatures that differ between cancer types and have associations with DNA mutational signatures. Given this unique dataset of RNA alterations, we also identified 1,012 genes significantly altered through both DNA and RNA mechanisms. Our study represents an extensive catalog of RNA alterations and reveals new insights into the heterogeneous molecular mechanisms of cancer gene alterations.

2017

A Pan-Cancer Transcriptome Analysis Reveals Pervasive Regulation through Tumor-Associated Alternative Promoters

Authors
Demircioglu, D; Kindermans, M; Nandi, T; Cukuroglu, E; Calabrese, C; Fonseca, NA; Kahles, A; Lehmann, K; Stegle, O; Brazma, A; Brooks, AN; Rätsch, G; Tan, P; Göke, J;

Publication

Abstract
ABSTRACTMost human protein-coding genes are regulated by multiple, distinct promoters, suggesting that the choice of promoter is as important as its level of transcriptional activity. While the role of promoters as driver elements in cancer has been recognized, the contribution of alternative promoters to regulation of the cancer transcriptome remains largely unexplored. Here we infer active promoters using RNA-Seq data from 1,188 cancer samples with matched whole genome sequencing data. We find that alternative promoters are a major contributor to context-specific regulation of isoform expression and that alternative promoters are frequently deregulated in cancer, affecting known cancer-genes and novel candidates. Our study suggests that a highly dynamic landscape of active promoters shapes the cancer transcriptome, opening many opportunities to further explore the interplay of regulatory mechanism and noncoding somatic mutations with transcriptional aberrations in cancer.

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