scholarly journals Critical Analysis of Strand-Biased Somatic Mutation Signatures in TP53 versus Ig Genes, in Genome-Wide Data and the Etiology of Cancer

ISRN Genomics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Robyn A. Lindley ◽  
Edward J. Steele

Previous analyses of rearranged immunoglobulin (Ig) variable genes (VDJs) concluded that the mechanism of Ig somatic hypermutation (SHM) involves the Ig pre-mRNA acting as a copying template resulting in characteristic strand biased somatic mutation patterns at A:T and G:C base pairs. We have since analysed cancer genome data and found the same mutation strand-biases, in toto or in part, in nonlymphoid cancers. Here we have analysed somatic mutations in a single well-characterised gene TP53. Our goal is to understand the genesis of the strand-biased mutation patterns in TP53—and in genome-wide data—that may arise by “endogenous” mechanisms as opposed to adduct-generated DNA-targeted strand-biased mutations caused by well-characterised “external” carcinogenic influences in cigarette smoke, UV-light, and certain dietary components. The underlying strand-biased mutation signatures in TP53, for many non-lymphoid cancers, bear a striking resemblance to the Ig SHM pattern. A similar pattern can be found in genome-wide somatic mutations in cancer genomes that have also mutated TP53. The analysis implies a role for base-modified RNA template intermediates coupled to reverse transcription in the genesis of many cancers. Thus Ig SHM may be inappropriately activated in many non-lymphoid tissues via hormonal and/or inflammation-related processes leading to cancer.

GigaScience ◽  
2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Taras K Oleksyk ◽  
Walter W Wolfsberger ◽  
Alexandra M Weber ◽  
Khrystyna Shchubelka ◽  
Olga T Oleksyk ◽  
...  

Abstract Background The main goal of this collaborative effort is to provide genome-wide data for the previously underrepresented population in Eastern Europe, and to provide cross-validation of the data from genome sequences and genotypes of the same individuals acquired by different technologies. We collected 97 genome-grade DNA samples from consented individuals representing major regions of Ukraine that were consented for public data release. BGISEQ-500 sequence data and genotypes by an Illumina GWAS chip were cross-validated on multiple samples and additionally referenced to 1 sample that has been resequenced by Illumina NovaSeq6000 S4 at high coverage. Results The genome data have been searched for genomic variation represented in this population, and a number of variants have been reported: large structural variants, indels, copy number variations, single-nucletide polymorphisms, and microsatellites. To our knowledge, this study provides the largest to-date survey of genetic variation in Ukraine, creating a public reference resource aiming to provide data for medical research in a large understudied population. Conclusions Our results indicate that the genetic diversity of the Ukrainian population is uniquely shaped by evolutionary and demographic forces and cannot be ignored in future genetic and biomedical studies. These data will contribute a wealth of new information bringing forth a wealth of novel, endemic and medically related alleles.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1538
Author(s):  
Ntombizethu Nokuphiwa Msomi ◽  
Tiara Padayachee ◽  
Nomfundo Nzuza ◽  
Puleng Rosinah Syed ◽  
Justyna Dorota Kryś ◽  
...  

The impact of lifestyle on shaping the genome content of an organism is a well-known phenomenon and cytochrome P450 enzymes (CYPs/P450s), heme-thiolate proteins that are ubiquitously present in organisms, are no exception. Recent studies focusing on a few bacterial species such as Streptomyces, Mycobacterium, Cyanobacteria and Firmicutes revealed that the impact of lifestyle affected the P450 repertoire in these species. However, this phenomenon needs to be understood in other bacterial species. We therefore performed genome data mining, annotation, phylogenetic analysis of P450s and their role in secondary metabolism in the bacterial class Gammaproteobacteria. Genome-wide data mining for P450s in 1261 Gammaproteobacterial species belonging to 161 genera revealed that only 169 species belonging to 41 genera have P450s. A total of 277 P450s found in 169 species grouped into 84 P450 families and 105 P450 subfamilies, where 38 new P450 families were found. Only 18% of P450s were found to be involved in secondary metabolism in Gammaproteobacterial species, as observed in Firmicutes as well. The pathogenic or commensal lifestyle of Gammaproteobacterial species influences them to such an extent that they have the lowest number of P450s compared to other bacterial species, indicating the impact of lifestyle on shaping the P450 repertoire. This study is the first report on comprehensive analysis of P450s in Gammaproteobacteria.


Blood ◽  
2000 ◽  
Vol 95 (9) ◽  
pp. 2922-2929 ◽  
Author(s):  
Wilhelmina M. Aarts ◽  
Richard J. Bende ◽  
Eric J. Steenbergen ◽  
Philip M. Kluin ◽  
Engelbert C. M. Ooms ◽  
...  

The expansion of follicular lymphomas (FLs) resembles, both morphologically and functionally, normal germinal center B-cell growth. The tumor cells proliferate in networks of follicular dendritic cells and are believed to be capable of somatic hypermutation and isotype switching. To investigate the relation between somatic mutation and heavy chain isotype expression, we analyzed the variable heavy (VH) chain genes of 30 FL samples of different isotypes. The VH genes of the FLs were heavily mutated (29.3 mutations on average). In addition, isotype-switched lymphomas contained more somatic mutations than immunoglobulin M–positive lymphomas (33.8 mutations per VH gene versus 23.0, respectively). In all but one of the FLs, the ratios of replacement versus silent mutations in the framework regions were low, independent of the absolute number of somatic mutations and the level of intraclonal variation. Analysis of relapse samples of 4 FLs showed no obvious increase in somatic mutation load in most FLs and a decrease in intraclonal variation in time. In 3 of 4 cases, we obtained evidence for selection of certain subclones, rather than clonal evolution. Our findings question if intraclonal variation is always a reflection of ongoing somatic hypermutation. This may have implications for the concept of antigen-driven lymphomagenesis.


2018 ◽  
Author(s):  
Casey W. Drubin ◽  
Avinash Ramu ◽  
Nicole B. Rockweiler ◽  
Donald F. Conrad

AbstractIntroductionOncogenic somatic mutations confer proliferative advantage and undergo positive clonal selection. We developed software and applied new analytical approaches to identify: (1) somatic mutations in diverse tissues, (2) somatically mutated genes under positive and negative selection, (3) post-transcriptional modifications in the mitochondrial transcriptome, and (4) inherited germline alleles predisposing people to higher somatic mutation burden or higher levels of post-transcriptional modification.MethodsTranscriptome sequence data (Genotype Tissue Expression project) for 7051 tissue samples from 549 postmortem donors and representing 44 tissue types were used. Germline mutations were inferred from whole-exome DNA sequencing and SNP arrays. DNA somatic mutations were inferred from variant allele frequencies (VAF) in RNA-seq data. Post-transcriptional modifications were inferred from Polymorphism Information Content (PIC) at the p9 sites of mitochondrial tRNA sequences. Positive and negative clonal selection was evaluated using a nonsynonomous/synonomous mutation rate (dN/dS) model. Genome-wide association studies (GWAS) were assessed with mitochondrial PIC for post-transcriptional modification level, or using the total number of somatic mutations observed per donor for somatic mutation burden.ResultsOur dN/dS model identified 78 genes under negative selection for somatic mutations (dN/dS < 1, padj< 0.05) and 14 under positive selection (dN/dS > 1, padj<0.05). Our GWAS identified 2 sites associated with post-transcriptional modification (1 approaching significance with p=5.99×10−8, 1 with p<5×10−8) and ∼20 sites associated with somatic mutation burden (p<5×10−8).ConclusionsTo our knowledge these are the first genome-wide association studies on normal somatic mutation burden. These studies were an attempt to increase understanding of the somatic mutation process. Our work identified somatic mutations at the global organismal level that may promote cell proliferation in a tissue-specific manner. By identifying tissue-specific mutations in actively expressed genes that appear before cancer phenotype is detected, this work also identifies gene candidates that might initiate tumorigenesis.


2021 ◽  
Vol 7 (3) ◽  
pp. eabd9036
Author(s):  
Sara Saez-Atienzar ◽  
Sara Bandres-Ciga ◽  
Rebekah G. Langston ◽  
Jonggeol J. Kim ◽  
Shing Wan Choi ◽  
...  

Despite the considerable progress in unraveling the genetic causes of amyotrophic lateral sclerosis (ALS), we do not fully understand the molecular mechanisms underlying the disease. We analyzed genome-wide data involving 78,500 individuals using a polygenic risk score approach to identify the biological pathways and cell types involved in ALS. This data-driven approach identified multiple aspects of the biology underlying the disease that resolved into broader themes, namely, neuron projection morphogenesis, membrane trafficking, and signal transduction mediated by ribonucleotides. We also found that genomic risk in ALS maps consistently to GABAergic interneurons and oligodendrocytes, as confirmed in human single-nucleus RNA-seq data. Using two-sample Mendelian randomization, we nominated six differentially expressed genes (ATG16L2, ACSL5, MAP1LC3A, MAPKAPK3, PLXNB2, and SCFD1) within the significant pathways as relevant to ALS. We conclude that the disparate genetic etiologies of this fatal neurological disease converge on a smaller number of final common pathways and cell types.


2021 ◽  
Vol 7 (13) ◽  
pp. eabe4414
Author(s):  
Guido Alberto Gnecchi-Ruscone ◽  
Elmira Khussainova ◽  
Nurzhibek Kahbatkyzy ◽  
Lyazzat Musralina ◽  
Maria A. Spyrou ◽  
...  

The Scythians were a multitude of horse-warrior nomad cultures dwelling in the Eurasian steppe during the first millennium BCE. Because of the lack of first-hand written records, little is known about the origins and relations among the different cultures. To address these questions, we produced genome-wide data for 111 ancient individuals retrieved from 39 archaeological sites from the first millennia BCE and CE across the Central Asian Steppe. We uncovered major admixture events in the Late Bronze Age forming the genetic substratum for two main Iron Age gene-pools emerging around the Altai and the Urals respectively. Their demise was mirrored by new genetic turnovers, linked to the spread of the eastern nomad empires in the first centuries CE. Compared to the high genetic heterogeneity of the past, the homogenization of the present-day Kazakhs gene pool is notable, likely a result of 400 years of strict exogamous social rules.


Nature ◽  
2021 ◽  
Vol 592 (7853) ◽  
pp. 253-257 ◽  
Author(s):  
Mateja Hajdinjak ◽  
Fabrizio Mafessoni ◽  
Laurits Skov ◽  
Benjamin Vernot ◽  
Alexander Hübner ◽  
...  

AbstractModern humans appeared in Europe by at least 45,000 years ago1–5, but the extent of their interactions with Neanderthals, who disappeared by about 40,000 years ago6, and their relationship to the broader expansion of modern humans outside Africa are poorly understood. Here we present genome-wide data from three individuals dated to between 45,930 and 42,580 years ago from Bacho Kiro Cave, Bulgaria1,2. They are the earliest Late Pleistocene modern humans known to have been recovered in Europe so far, and were found in association with an Initial Upper Palaeolithic artefact assemblage. Unlike two previously studied individuals of similar ages from Romania7 and Siberia8 who did not contribute detectably to later populations, these individuals are more closely related to present-day and ancient populations in East Asia and the Americas than to later west Eurasian populations. This indicates that they belonged to a modern human migration into Europe that was not previously known from the genetic record, and provides evidence that there was at least some continuity between the earliest modern humans in Europe and later people in Eurasia. Moreover, we find that all three individuals had Neanderthal ancestors a few generations back in their family history, confirming that the first European modern humans mixed with Neanderthals and suggesting that such mixing could have been common.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Tarun Karthik Kumar Mamidi ◽  
Jiande Wu ◽  
Chindo Hicks

Background. A majority of prostate cancers (PCas) are indolent and cause no harm even without treatment. However, a significant proportion of patients with PCa have aggressive tumors that progress rapidly to metastatic disease and are often lethal. PCa develops through somatic mutagenesis, but emerging evidence suggests that germline genetic variation can markedly contribute to tumorigenesis. However, the causal association between genetic susceptibility and tumorigenesis has not been well characterized. The objective of this study was to map the germline and somatic mutation interaction landscape in indolent and aggressive tumors and to discover signatures of mutated genes associated with each type and distinguishing the two types of PCa. Materials and Methods. We integrated germline mutation information from genome-wide association studies (GWAS) with somatic mutation information from The Cancer Genome Atlas (TCGA) using gene expression data from TCGA on indolent and aggressive PCas as the intermediate phenotypes. Germline and somatic mutated genes associated with each type of PCa were functionally characterized using network and pathway analysis. Results. We discovered gene signatures containing germline and somatic mutations associated with each type and distinguishing the two types of PCa. We discovered multiple gene regulatory networks and signaling pathways enriched with germline and somatic mutations including axon guidance, RAR, WINT, MSP-RON, STAT3, PI3K, TR/RxR, and molecular mechanisms of cancer, NF-kB, prostate cancer, GP6, androgen, and VEGF signaling pathways for indolent PCa and MSP-RON, axon guidance, RAR, adipogenesis, and molecular mechanisms of cancer and NF-kB signaling pathways for aggressive PCa. Conclusion. The investigation revealed germline and somatic mutated genes associated with indolent and aggressive PCas and distinguishing the two types of PCa. The study revealed multiple gene regulatory networks and signaling pathways dysregulated by germline and somatic alterations. Integrative analysis combining germline and somatic mutations is a powerful approach to mapping germline and somatic mutation interaction landscape.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Pierpaolo Maisano Delser ◽  
Eppie R. Jones ◽  
Anahit Hovhannisyan ◽  
Lara Cassidy ◽  
Ron Pinhasi ◽  
...  

AbstractOver the last few years, genome-wide data for a large number of ancient human samples have been collected. Whilst datasets of captured SNPs have been collated, high coverage shotgun genomes (which are relatively few but allow certain types of analyses not possible with ascertained captured SNPs) have to be reprocessed by individual groups from raw reads. This task is computationally intensive. Here, we release a dataset including 35 whole-genome sequenced samples, previously published and distributed worldwide, together with the genetic pipeline used to process them. The dataset contains 72,041,355 sites called across 19 ancient and 16 modern individuals and includes sequence data from four previously published ancient samples which we sequenced to higher coverage (10–18x). Such a resource will allow researchers to analyse their new samples with the same genetic pipeline and directly compare them to the reference dataset without re-processing published samples. Moreover, this dataset can be easily expanded to increase the sample distribution both across time and space.


PLoS ONE ◽  
2018 ◽  
Vol 13 (9) ◽  
pp. e0202890 ◽  
Author(s):  
Zsolt Bánfai ◽  
Valerián Ádám ◽  
Etelka Pöstyéni ◽  
Gergely Büki ◽  
Márta Czakó ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document