As rhodopsin-like receptor, 7tm_1 domain comprises the group of G protein-coupled receptor and encompasses a wide range of functions such as various autocrine, paracrine, and endocrine processes. By contrast, HLTU has none hotspot and THCA has only one hotspot mutation in ILF3 (N192). There were several methods focused on predicting driver mutations, such as E-Driver [17], MuSiC [18] and OncodriveCLUST [19]. 1-3 It was reported that some synonymous mutations could affect messenger RNA (mRNA) splicing 4 and the splicing patterns might consequently affect the biological processes. Thirty-five different Pfam domains were detected in the proteins under which the hotspot mutations occurred, whereas 29 and 91 protein domains under which neutral synonymous and non-hotspot mutations happened, respectively. And then, we nominated synonymous hotspot mutations as candidate drivers based on the mutational rates across different sequence contexts and investigated the features (such as conservation, distribution of amino acids and protein domains undergo mutations) of hotspots, neutral synonymous mutations and non-hotspots in the hotspot-mutation-containing-genes (HMCGs). 2000;79:18–22. A mutation is any type of alteration or change in DNA that is permanent. Question: Synonymous Mutations And Their Effect On Splice Site. Other statistical analyses were performed by GraphPad Prism 5 (GraphPad Software). Almost every research paper that I have read pertaining to this topic has always used the term "synonymous mutation" irrespective of whether or not it has a phenotypic effect. Among these nine domains, the Ion_trans domain is the most frequent one (28 items), but the proportion of hotspots is less than those of neutral synonymous mutations and non-hotspots (Fig. (Upper) The nucleotide and amino acid composition (in one letter code) of part of the human CFTR exon 12 (hCF). Download : Download high-res image (129KB)Download : Download full-size image. In a rather general sense, a gain in understanding of the association between genetic variation and its phenotypic effects is therefore a step toward grasping how nature act… Lancet Oncol. 2010;11:174. BMC Bioinformatics. DNA methylation in glioblastoma: impact on gene expression and clinical outcome. Similar with the distributions of mutational types in TCGA dataset, the most frequency mutational nucleotide changes in 1000G dataset are also C → T and G → A transitions (Fig. Cancer Res. 2017;38:839–48. The authors thank all members of our laboratory for their valuable discussions. Cancer genomes not only contain cancer-causing driver mutations, but also many additional accumulated passenger mutations without direct relation to the tumor phenotype. Relative to nonsynonymous mutations, synonymous muta- tions are thought to face at most modest selection, and have thus been used to estimate neutral mutation rates for many decades. PLoS Comput Biol. PubMed 1993;10:512–26. GPR116, an adhesion G-protein-coupled receptor, promotes breast cancer metastasis via the Galphaq-p63RhoGEF-rho GTPase pathway. Previous study has proposed that special A/T-rich sequence binding protein acts as a global chromatin organizer for metastatic activity by controlling gene expression [43]. Griseri P, Bourcier C, Hieblot C, Essafi-Benkhadir K, Chamorey E, Touriol C, Pages G. A synonymous polymorphism of the Tristetraprolin (TTP) gene, an AU-rich mRNA-binding protein, affects translation efficiency and response to Herceptin treatment in breast cancer patients. ‘All’ in this figure represents the average proportions of mutational types across 15 cancer types. 2014;156:1324–35. 1988;78:151–5. However, this does not mean that synonymous mutations are free from natural selection. 2011;12:32–42. Google Scholar. BMC Genomics. Melanoma's high C>T mutation rate: is deamination playing a role? 2013;502:333–9. The p53 tumor suppressor (TP53) also has recurrent synonymous mutations, but, in contrast to those in oncogenes, these are adjacent to splice sites and inactivate them. PubMed The authors declare that they have no competing interests. 2005;571:19–31. Genetic variation drives evolution. But in this study, we just performed a pan-cancer analyzed of the hotspots. 2010;6:e1001025. Synonymous mutations also significantly cluster in known oncogenes (Figure 3E) and even more so in the top-16 oncogene set, where a synonymous mutation is more likely to occur within five codons of another synonymous-mutated site (OR = 1.74, p = 10 −6; Figure 3E), an effect size similar to the missense-missense clustering in the same genes (OR = 1.92; Figure 3F). Distribution of synonymous hotspot mutations across cancer types and genes. It is found that the percentage of transitions between C and T preceded that between A and G, which is known to be a general property of DNA sequence change and evolution [42]. Synonymous mutations can affect transcription, splicing, mRNA transport, and translation, any of which could alter phenotype, rendering the synonymous mutation non-silent. IGF-1R expression was lower in the BM group than in the LP group both in terms of transcription and … A pan-cancer catalogue of cancer driver protein interaction interfaces. Synonymous mutations, however, are intuitively thought to be functionally silent and evolutionarily neutral. Additionally, more recent studies have indicated that different substitution types, codon usage bias and hotspot mutational positions in base sequence could be associated with different biological processes and cancer types [2, 22, 23]. DNA sequence evolution: the sounds of silence. Naturally occurring neomorphic PIK3R1 mutations activate the MAPK pathway, dictating therapeutic response to MAPK pathway inhibitors. Nature. The cancer related synonymous mutations in TCGA were downloaded from COSMIC v79 (Catalogue of Somatic Mutations in Cancer) [25]. Hum Mutat. In human genes, roughly 99.8% of DNA sequence variations do not alter the primary sequences of proteins (1), and synonymous SNPs show a higher frequency than both missense SNPs and the SNPs in the non-coding regions (1,2). a Venn diagram showing the number of domain types for the multiple intersections among hotspot mutations, neutral synonymous mutations and non-hotspot mutations. 6). And this transition is associated with two of four Ala’s codons, but independent of the transformation between optimal and non-optimal codons [10]. And the common and diverse mutational signatures among hotspot mutations, neutral synonymous mutations of HCMGs in 1000G and non-hotspot mutations of HCMGs in TCGA were also detected. 3a), which correspond to the NC_GCts and ATtv sequence contexts, respectively. volume 20, Article number: 190 (2019) Orange bar represents the proportion of mutations in TCGA and grey bar represents that in 1000G. SFAPS: an R package for structure/function analysis of protein sequences based on informational spectrum method. Curr Opin Struc Biol. The roughly 10,000 variants in the coding region of every human genome that have no effect on the resulting product protein sequence are termed synonymous SNVs (sSNVs) (Shen et al., 2013). Distribution of 12 possible mutational nucleotide substitution patterns of synonymous mutations across the 15 cancer types was shown in Fig. 2003;13:838–44. Methods. To acquire insight into the characters of pathogenic and neutral synonymous mutations between cancer and benign samples, the differences of synonymous mutations at nucleotide and amino acid levels (such as nucleotide substitutions, mutational positions of codon and distribution of amino acids at which synonymous mutations happened) were investigated between datasets in TCGA and the 1000 Genomes Project (1000G) (as neutral samples) [16]. Moreover, the average numbers of variants per sample across 15 cancer types are different with each other (the lower panel of Fig. 2000;101:425–33. XW, LZ and PW helped perform the analysis. The result indicated that there were significant differences in conservation, amino acids and domain characterization between hotspots and neutral synonymous mutations. Evidence for purifying selection against synonymous mutations in mammalian exonic splicing enhancers. Selection on synonymous mutations in oncogenes is cancer-type specific, and although the functional consequences of cancer-associated synonymous mutations may be diverse, they recurrently alter exonic motifs that regulate splicing and are associated with changes in oncogene splicing in tumors. We estimate that between one in two and one in five silent mutations in oncogenes have been selected, equating to ∼6%– 8% of all selected single-nucleotide changes in these genes. 4a), the number of hotspot mutations under NC_GCts sequence context (consists of C:G → T:A transitions) is the largest one compared with the other types, and that under ATtv (consists of A:T → C:G and A↔T transversions) is the least one. Genomes Project Consortium. We will attack these problems in our further work. This article has been published as part of BMC Medical Genetics Volume 20 Supplement 2, 2019: Proceedings of the 2018 International Conference on Intelligent Computing (ICIC 2018) and Intelligent Computing and Biomedical Informatics (ICBI) 2018 conference: medical genetics. In hotspot mutation dataset, L and Phe (12.37 and 11.34%, respectively) are the most mutated amino acids due to prevalent C → T transition, which is involved the transformation between optimal and non-optimal codons. Synonymous mutations have been identified to play important roles in cancer development, although they do not modify the protein sequences. These three datasets were applied for the further functional analyses, for example, conservation, amino acids and protein domains under which mutations occurred. Synonymous mutations, which occur in the gene-coding regions without changing the encoded amino acids, have long been supposed to be silent for the fitness of organisms and neutral during evolution [1]. Notable among these outliers are SKCA, ENAD, STAD and LUAD, which contain more than 100 synonymous mutations per sample. Furthermore, the efficient codon replacing with a less efficient one could affect protein synthesis. Mutational landscape and significance across 12 major cancer types. Nat Methods. If we add the possibility of weak effects of translational rate/accuracy and an otherwise mysteriouseffectofsynonymousnucleotidecontentonmRNA levels,(47) mediated at either the transcriptional or RNA- 2014;23:551–2. Correlation between percentages of synonymous mutations and codon numbers of amino acids in TCGA and 1000G. Mutat Res. Chen T, Wang Z, Zhou W, Chong Z, Meric-Bernstam F, Mills GB, Chen K. Hotspot mutations delineating diverse mutational signatures and biological utilities across cancer types. Nik-Zainal S, Alexandrov LB, Wedge DC, Van Loo P, Greenman CD, Raine K, Jones D, Hinton J, Marshall J, Stebbings LA. Noisy synonymous mutations may also influence the way the mRNA folds, which can in turn perturb the translation process, or they can interfere with the binding of microRNAs, possibly disrupting normal regulation. Nevertheless, those studies mainly focused on the missense mutations and ignored the potential functions of synonymous mutations. In addition, to estimate the important synonymous mutations for pan-cancer, the distribution of hotspot mutations across different genes was analyzed (Additional file 1: Figure S3B). 2016;8:442–57. Carcinogenesis. The RS score of hotspot mutation dataset is significant higher than that neutral synonymous mutation dataset (p-value <2e-16). synonymous and nonsynonymous mutations in coagu-lation Factor VIII illustrates a general strategy for inves-tigators to score synonymous mutations [28]. Cancer associated synonymous mutations have the tendency to become A/T-rich. The Pfam protein families database: towards a more sustainable future. Our study suggested that synonymous mutations in the MDR1 haplotype produce a subtle but measurable change in substrate binding site conformation. Article The datasets supporting the conclusions of this article are included within the article and its additional files. Google Scholar. Buske OJ, Manickaraj A, Mital S, Ray PN, Brudno M. Identification of deleterious synonymous variants in human genomes. PubMed Central However, for neutral mutation dataset, the most frequent substitutions are under Ala (14.44%), which is largely tolerated outside functional site as the smallest residues can be fitted into structures easily. CAS Upper panel: blue and yellow bars represent the proportions of synonymous variants and corresponding tumor samples, respectively. Genome Res. As a result of signature smoke exposure, LUAD has an increased C → A transversions [33]. 2013;4:312. However, this conservative concept begins to be rebutted by two lines of evidence: first one is the understanding of synonymous mutational effect on protein synthesis and folding; second, codon usage bias reveals that synonymous codons are under evolutionary pressure [2]. Here, we present evidence that these “silent” mutations frequently contribute to human cancer. Cheung LWT, Yu S, Zhang D, Li J, Ng PKS, Panupinthu N, Mitra S, Ju Z, Yu Q, Liang H, et al. Lastly, in this study, to avoid the bias of background number of passenger mutations, we only selected the hotspot mutations that predicted as the pathogenic mutations by Functional Analysis through Hidden Markov Models [25]. 2002;21:7435. BMC Evol Biol. Synonymous mutations, which occur in the gene-coding regions without changing the encoded amino acids, have long been supposed to be silent for the fitness of organisms and neutral during evolution [].However, this conservative concept begins to be rebutted by two lines of evidence: first one is the understanding of synonymous mutational effect on protein synthesis and folding; second, … 2016;44:D279–D85. However, relatively little research has specifically delineated the functionality of synonymous mutations in cancer. PubMed In this study, two haplotypes of Igf1r with four synonymous mutations in the coding sequences of IGF-1R ECD between large pigs (LP) and Bama pigs (BM) were stably expressed in the Igf1r-knockout MC3T3-E1 cells and named as MC3T3-LP cells (LP group) and MC3T3-BM cells (BM group), respectively. Pfeifer GP, You YH, Besaratinia A. Mutations induced by ultraviolet light. There is none synonymous mutation under Met and Trp due to the lack of synonymous codons. Nat Rev Genet. 2014;26:479–94. Synonymous changes may not be neutral because certain codons are translated more efficiently (faster and/or more accurately) than others. Forbes SA, Beare D, Gunasekaran P, Leung K, Bindal N, Boutselakis H, Ding M, Bamford S, Cole C, Ward S. COSMIC: exploring the world's knowledge of somatic mutations in human cancer. In addition, we mapped hotspots, neutral and non-hotspot mutations of hotspot-mutation-containing-genes to their respective protein domains and found ion transport domain was the most frequent one, which could mediate the cell interaction and had relevant implication for tumor therapy. Kobe B, Kajava AV. Synonymous SNPs are the most polymorphic, indicating that most such m… In addition, some studies have identified that synonymous mutations frequently act as driver mutations in human cancers [10, 11] and can affect clinical outcome or treatment response [12,13,14]. For the comprehensiveness of analysis, this study not only highlights the nucleotide level preferences, but also amino acids level, and especially hotspot mutations. Moreover, due to the overabundance of synonymous sites involved in CpG dinucleotides, the mutation rate in exons is 30~60% higher than that in the non-coding regions [41]. YB performed the analysis and drafted the manuscript. Mutational signatures of synonymous mutations in TCGA and 1000G. However, the analysis of synonymous mutation distribution in Ion_trans domain is opposite with the previous analysis of missense mutations [46], which may be due to the different pathogenic mechanisms of synonymous and non-synonymous mutations. As an important amino acid of leucine-rich repeats, L is associated with a versatile structural framework for the formation of protein-protein interactions [49]. The aim of 1000G is to discover variants with a frequency of occurrence > 1% in multiple human populations worldwide. Nature. The observation could add perspective to understand cancer-related synonymous mutations. 2, 3, 4, and 6 codon represent the numbers of synonymous codons, respectively. Firstly, synonymous mutations were analyzed between TCGA and 1000 Genomes Project at nucleotide and amino acid levels. Ma F, Sun T, Shi Y, Yu D, Tan W, Yang M, Wu C, Chu D, Sun Y, Xu B, et al. A p-value < 0.05 is considered to be significant. P Natl Acad Sci Usa. Correspondence to Secondly, the consistent patterns and specificity of hotspots in individual cancer are important and should be explored. 2010;467:1061–73. b Bar diagram where the value 100% represents the total number of mutations under different sequence contexts distributed in each cancer type. Cell. Polymorphisms of EGFR predict clinical outcome in advanced non-small-cell lung cancer patients treated with Gefitinib. 2014;35:643–53. 3b). Vast literature is available, if you Google Selection acts on synonymous mutations in oncogenes in human cancers, These mutations frequently alter exonic splicing motifs and affect mRNA splicing, TP53 also has recurrent synonymous mutations, but these inactivate splice sites, Dosage-sensitive oncogenes have recurrent mutations in their 3′ UTRs. Among non-hotspot mutations, the most frequent substitutions are under L (14.51%). PubMed As seen in the upper panel of Fig. By using this website, you agree to our The full contents of the supplement are available online at https://bmcmedgenet.biomedcentral.com/articles/supplements/volume-20-supplement-2. 4b, the most widespread sequence context undergoes hotspots is NC_GCts sequence context, which presents in 14 cancer types. Studies have shown that nucleotide substitutions, including synonymous mutations, could be related to carcinogen exposures and DNA repair processes [35,36,37]. Schaafsma GC, Vihinen M. Large differences in proportions of harmful and benign amino acid substitutions between proteins and diseases. Moreover, the most frequently substituted bases are C and G, and the most frequently mutated to bases are T and A. We also investigated the domain compositions of the proteins, under which hotspot mutations, neutral synonymous mutations of HMCGs in 1000G and non-hotspot mutations of HMCGs in TCGA occurred. It is now known that synonymous mutations can either reduce or enhance protein synthesis. Article 7tm_1 domain is the highest proportion of hotspot mutations and consists of the group of G protein-coupled receptor, which could promote cancer metastasis [52]. Moreover, in CEAD and THCA, the hotspots are only enriched in NC_GCts. Neutral selection is essentially driven by mutation and genetic drift and implies an equal number of synonymous versus nonsynonymous substitutions; the ω values will be approximately 1. 1, with regard to synonymous mutation proportion (blue bar), SKCA is the largest and HLTU the smallest. resolved mechanisms by which synonymous mutations can have an effect on fitness: splice regulation, miRNA binding, mRNA folding and protein folding. In this study, we not only investigated the distribution and mutational nucleotide changes of synonymous mutations across 15 cancer types, but also made the comparison of synonymous mutational signatures between TCGA and 1000G at nucleotide and amino acid levels.