Nonsynonymous, synonymous and nonsense mutations in human cancer-related genes undergo stronger purifying selections than expectation

Convergent evolution of allele-specific gene expression that leads to non-small cell lung cancer in different human populations

Phenotypical innovations during evolution are caused by novel mutations, which are usually heterozygous at the beginning. The gene expressions on two alleles of these mutation sites are not necessarily identical, leading to flexible allele-specific regulation in cell systems. We retrieve the transcriptome data of normal and non-small cell lung cancer (NSCLC) tissues from 47 African Americans (AA) and 50 European Americans (EA). We analyze the differentially expressed genes (DEGs) in NSCLC as well as the tumor-specific mutations. Expression and mutation profiles show convergent evolution in AA and EA populations. The tumor-specific mutations are poorly overlapped, but many of them are located in the same genes, mainly oncogenes and tumor suppressor genes. The DEGs in tumors are majorly caused by the mutated alleles rather than normal alleles. The relative expressions of mutated alleles are highly correlated between AA and EA. The differential expression in NSCLC is predominantly mediated by the mutated alleles on heterozygous sites. This molecular mechanism underlying NSCLC oncogenesis is conserved across different human populations, exhibiting convergent evolution. We present this novel angle that differential expression analysis should be performed separately for different alleles. Our ideas should greatly benefit the cancer community.

Understanding the impact of ABCG2 polymorphisms on drug pharmacokinetics: focus on rosuvastatin and allopurinol

INTRODUCTION

In addition to the well-established understanding of the pharmacogenetics of drug-metabolizing enzymes, there is growing data on the effects of genetic variation in drug transporters, particularly ATP-binding cassette (ABC) transporters. However, the evidence that these genetic variants can be used to predict drug effects and to adjust individual dosing to avoid adverse events is still limited.

AREAS COVERED

This review presents a summary of the current literature from the PubMed database as of February 2024 regarding the impact of genetic variants on ABCG2 function and their relevance to the clinical use of the HMG-CoA reductase inhibitor rosuvastatin and the xanthine oxidase inhibitor allopurinol.

EXPERT OPINION

Although there are pharmacogenetic guidelines for the ABCG2 missense variant Q141K, there is still some conflicting data regarding the clinical benefits of these recommendations. Some caution appears to be warranted in homozygous ABCG2 Q141K carriers when rosuvastatin is administered at higher doses and such information is already included in the drug label. The benefit of dose adaption to lower possible side effects needs to be evaluated in prospective clinical studies.

Effects of urban-induced mutations on ecology, evolution and health

Increasing evidence suggests that urbanization is associated with higher mutation rates, which can affect the health and evolution of organisms that inhabit cities. Elevated pollution levels in urban areas can induce DNA damage, leading to de novo mutations. Studies on mutations induced by urban pollution are most prevalent in humans and microorganisms, whereas studies of non-human eukaryotes are rare, even though increased mutation rates have the potential to affect organisms and their populations in contemporary time. Our Perspective explores how higher mutation rates in urban environments could impact the fitness, ecology and evolution of populations. Most mutations will be neutral or deleterious, and higher mutation rates associated with elevated pollution in urban populations can increase the risk of cancer in humans and potentially other species. We highlight the potential for urban-driven increased deleterious mutational loads in some organisms, which could lead to a decline in population growth of a wide diversity of organisms. Although beneficial mutations are expected to be rare, we argue that higher mutation rates in urban areas could influence adaptive evolution, especially in organisms with short generation times. Finally, we explore avenues for future research to better understand the effects of urban-induced mutations on the fitness, ecology and evolution of city-dwelling organisms.

Tumor Mutation Burden as a Cornerstone in Precision Oncology Landscapes: Effect of Panel Size and Uncertainty in Cutoffs

Tumor mutation burden (TMB) has profound implications for personalized cancer therapy, particularly immunotherapy. However, the size of the panel and the cutoff values for an accurate determination of TMB are still controversial. In this study, a pan-cancer analysis was performed on 22 cancer types from The Cancer Genome Atlas. The efficiency of gene panels of different sizes and the effect of cutoff values in accurate TMB determination was assessed on a large cohort using Whole Exome Sequencing data (n = 9929 patients) as the gold standard. Gene panels of four different sizes (i.e., 0.44-2.54 Mb) were selected for comparative analyses. The heterogeneity of TMB within and between cancer types is observed to be very high, and it becomes possible to obtain the exact TMB value as the size of the panel increases. In panels with limited size, it is particularly difficult to recognize patients with low TMB. In addition, the use of a general TMB cutoff can be quite misleading. The optimal cutoff value varies between 5 and 20, depending on the TMB distribution of the different tumor types. The use of comprehensive gene panels and the optimization of TMB cutoff values for different cancer types can make TMB a robust biomarker in precision oncology. Moreover, optimization of TMB can help accelerate translational medicine research, and by extension, delivery of personalized cancer care in the future.

The importance of protein domain mutations in cancer therapy

Cancer is a complex disease that is caused by multiple genetic factors. Researchers have been studying protein domain mutations to understand how they affect the progression and treatment of cancer. These mutations can significantly impact the development and spread of cancer by changing the protein structure, function, and signalling pathways. As a result, there is a growing interest in how these mutations can be used as prognostic indicators for cancer prognosis. Recent studies have shown that protein domain mutations can provide valuable information about the severity of the disease and the patient's response to treatment. They may also be used to predict the response and resistance to targeted therapy in cancer treatment. The clinical implications of protein domain mutations in cancer are significant, and they are regarded as essential biomarkers in oncology. However, additional techniques and approaches are required to characterize changes in protein domains and predict their functional effects. Machine learning and other computational tools offer promising solutions to this challenge, enabling the prediction of the impact of mutations on protein structure and function. Such predictions can aid in the clinical interpretation of genetic information. Furthermore, the development of genome editing tools like CRISPR/Cas9 has made it possible to validate the functional significance of mutants more efficiently and accurately. In conclusion, protein domain mutations hold great promise as prognostic and predictive biomarkers in cancer. Overall, considerable research is still needed to better define genetic and molecular heterogeneity and to resolve the challenges that remain, so that their full potential can be realized.

Identification and mechanism determination of the efflux pump subunit amrB gene mutations linked to gentamicin susceptibility in clinical Burkholderia pseudomallei from Malaysian Borneo

The bacterium Burkholderia pseudomallei is typically resistant to gentamicin but rare susceptible strains have been isolated in certain regions, such as Thailand and Sarawak, Malaysia. Recently, several amino acid substitutions have been reported in the amrB gene (a subunit of the amrAB-oprA efflux pump gene) that confer gentamicin susceptibility. However, information regarding the mechanism of the substitutions conferring the susceptibility is lacking. To understand the mechanism of amino acid substitution that confers susceptibility, this study identifies the corresponding mutations in clinical gentamicin-susceptible B. pseudomallei isolates from the Malaysian Borneo (n = 46; Sarawak: 5; Sabah: 41). Three phenotypically confirmed gentamicin-susceptible (GENs) strains from Sarawak, Malaysia, were screened for mutations in the amrB gene using gene sequences of gentamicin-resistant (GENr) strains (QEH 56, QEH 57, QEH20, and QEH26) and publicly available sequences (AF072887.1 and BX571965.1) as the comparator. The effect of missense mutations on the stability of the AmrB protein was determined by calculating the average energy change value (ΔΔG). Mutagenesis analysis identified a polymorphism-associated mutation, g.1056 T > G, a possible susceptible-associated in-frame deletion, Delta V412, and a previously confirmed susceptible-associated amino acid substitution, T368R, in each of the three GENs isolates. The contribution of Delta V412 needs further confirmation by experimental mutagenesis analysis. The mechanism by which T368R confers susceptibility, as elucidated by in silico mutagenesis analysis using AmrB-modeled protein structures, is proposed to be due to the location of T368R in a highly conserved region, rather than destabilization of the AmrB protein structure.

Liver cancer-specific mutations in functional domains of ADAR2 lead to the elevation of coding and non-coding RNA editing in multiple tumor-related genes

Mutation is the major cause of phenotypic innovations. Apart from DNA mutations, the alteration on RNA such as the ADAR-mediated A-to-I RNA editing could also shape the phenotype. These two layers of variations have not been systematically combined to study their collective roles in cancers. We collected the high-quality transcriptomes of ten hepatocellular carcinoma (HCC) and the matched control samples. We systematically identified HCC-specific mutations in the exonic regions and profiled the A-to-I RNA editome in each sample. All ten HCC samples had mutations in the CDS of ADAR2 gene (dsRNA-binding domain or catalytic domain). The consequence of these mutations converged to the elevation of ADAR2 efficiency as reflected by the global increase of RNA editing levels in HCC. The up-regulated editing sites (UES) were enriched in the CDS and UTR of oncogenes and tumor suppressor genes (TSG), indicating the possible roles of these target genes in HCC oncogenesis. We present the mutation-ADAR2-UES-oncogene/TSG-HCC axis that explains how mutations at different layers would finally lead to abnormal phenotype. In the light of central dogma, our work provides novel insights into how to fully take advantage of the transcriptome data to decipher the consequence of mutations.

Rational peptide design for targeting cancer cell invasion

Cell invasion is an important process in cancer progression and recurrence. Invasion and implantation of cancer cells from their original place to other tissues, by disabling vital organs, challenges the treatment of cancer patients. Given the importance of the matter, many molecular treatments have been developed to inhibit cancer cell invasion. Because of their low production cost and ease of production, peptides are valuable therapeutic molecules for inhibiting cancer cell invasion. In recent years, advances in the field of computational biology have facilitated the design of anti-cancer peptides. In our investigation, using computational biology approaches such as evolutionary analysis, residue scanning, protein-peptide interaction analysis, molecular dynamics, and free energy analysis, our team designed a peptide library with about 100 000 candidates based on A6 (acetyl-KPSSPPEE-amino) sequence which is an anti-invasion peptide. During computational studies, two of the designed peptides that give the highest scores and showed the greatest sequence similarity to A6 were entered into the experimental analysis workflow for further analysis. In experimental analysis steps, the anti-metastatic potency and other therapeutic effects of designed peptides were evaluated using MTT assay, RT-qPCR, zymography analysis, and invasion assay. Our study disclosed that the IK1 (acetyl-RPSFPPEE-amino) peptide, like A6, has great potency to inhibit the invasion of cancer cells.

Incorporating mutational heterogeneity to identify genes that are enriched for synonymous mutations in cancer

BACKGROUND

Synonymous mutations, which change the DNA sequence but not the encoded protein sequence, can affect protein structure and function, mRNA maturation, and mRNA half-lives. The possibility that synonymous mutations might be enriched in cancer has been explored in several recent studies. However, none of these studies control for all three types of mutational heterogeneity (patient, histology, and gene) that are known to affect the accurate identification of non-synonymous cancer-associated genes. Our goal is to adopt the current standard for non-synonymous mutations in an investigation of synonymous mutations.

RESULTS

Here, we create an algorithm, MutSigCVsyn, an adaptation of MutSigCV, to identify cancer-associated genes that are enriched for synonymous mutations based on a non-coding background model that takes into account the mutational heterogeneity across these levels. Using MutSigCVsyn, we first analyzed 2572 cancer whole-genome samples from the Pan-cancer Analysis of Whole Genomes (PCAWG) to identify non-synonymous cancer drivers as a quality control. Indicative of the algorithm accuracy we find that 58.6% of these candidate genes were also found in Cancer Census Gene (CGC) list, and 66.2% were found within the PCAWG cancer driver list. We then applied it to identify 30 putative cancer-associated genes that are enriched for synonymous mutations within the same samples. One of the promising gene candidates is the B cell lymphoma 2 (BCL-2) gene. BCL-2 regulates apoptosis by antagonizing the action of proapoptotic BCL-2 family member proteins. The synonymous mutations in BCL2 are enriched in its anti-apoptotic domain and likely play a role in cancer cell proliferation.

CONCLUSION

Our study introduces MutSigCVsyn, an algorithm that accounts for mutational heterogeneity at patient, histology, and gene levels, to identify cancer-associated genes that are enriched for synonymous mutations using whole genome sequencing data. We identified 30 putative candidate genes that will benefit from future experimental studies on the role of synonymous mutations in cancer biology.

SARS-CoV-2 continuously optimizes its codon usage to adapt to human lung environment

Viruses need to utilize the resources from host cells to reproduce themselves. RNA translation rate, which is largely determined by codon usage, is the rate-limiting step across the life cycle of viruses. Adapting to the codon usage of hosts would help virus better proliferate. We retrieved the time-course mutation profile of millions of world-wide SARS-CoV-2 sequences. For synonymous mutations, we defined whether a mutation elevate or reduce the relative synonymous codon usage (RSCU). We found that if a synonymous mutation in SARS-CoV-2 increases the RSCU (calculated from human lungs), denoted as delta RSCU > 0, then this mutation is positively selected because the allele frequency (AF) of this mutation increases with time, and vice versa. The results suggest that in SARS-CoV-2, the synonymous mutations that increase codon optimality are beneficial to the virus and are favored by natural selection. For the first time, we used the dynamics of allele frequency to demonstrate that SARS-CoV-2 is continuously optimizing its codon usage to adapt to human lungs. Nevertheless, adaptation to other human tissues cannot be excluded. These results warn us that under this global pandemic, synonymous mutations in SARS-CoV-2 should not be automatically ignored since they indeed change the fitness of the virus.

Constructing gene similarity networks using co-occurrence probabilities

Gene similarity networks play important role in unraveling the intricate associations within diverse cancer types. Conventionally, gauging the similarity between genes has been approached through experimental methodologies involving chemical and molecular analyses, or through the lens of mathematical techniques. However, in our work, we have pioneered a distinctive mathematical framework, one rooted in the co-occurrence of attribute values and single point mutations, thereby establishing a novel approach for quantifying the dissimilarity or similarity among genes. Central to our approach is the recognition of mutations as key players in the evolutionary trajectory of cancer. Anchored in this understanding, our methodology hinges on the consideration of two categorical attributes: mutation type and nucleotide change. These attributes are pivotal, as they encapsulate the critical variations that can precipitate substantial changes in gene behavior and ultimately influence disease progression. Our study takes on the challenge of formulating similarity measures that are intrinsic to genes' categorical data. Taking into account the co-occurrence probability of attribute values within single point mutations, our innovative mathematical approach surpasses the boundaries of conventional methods. We thereby provide a robust and comprehensive means to assess gene similarity and take a significant step forward in refining the tools available for uncovering the subtle yet impactful associations within the complex realm of gene interactions in cancer.

Molecular characterization of G6PD mutations identifies new mutations and a high frequency of intronic variants in Thai females

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymopathy caused by mutations in the G6PD gene. A medical concern associated with G6PD deficiency is acute hemolytic anemia induced by certain foods, drugs, and infections. Although phenotypic tests can correctly identify hemizygous males, as well as homozygous and compound heterozygous females, heterozygous females with a wide range of G6PD activity may be misclassified as normal. This study aimed to develop multiplex high-resolution melting (HRM) analyses to enable the accurate detection of G6PD mutations, especially among females with heterozygous deficiency. Multiplex HRM assays were developed to detect six G6PD variants, i.e., G6PD Gaohe (c.95A>G), G6PD Chinese-4 (c.392G>T), G6PD Mahidol (c.487G>A), G6PD Viangchan (c.871G>A), G6PD Chinese-5 (c.1024C>T), and G6PD Union (c.1360C>T) in two reactions. The assays were validated and then applied to genotype G6PD mutations in 248 Thai females. The sensitivity of the HRM assays developed was 100% [95% confidence interval (CI): 94.40%-100%] with a specificity of 100% (95% CI: 88.78%-100%) for detecting these six mutations. The prevalence of G6PD deficiency was estimated as 3.63% (9/248) for G6PD deficiency and 31.05% (77/248) for intermediate deficiency by phenotypic assay. The developed HRM assays identified three participants with normal enzyme activity as heterozygous for G6PD Viangchan. Interestingly, a deletion in intron 5 nucleotide position 637/638 (c.486-34delT) was also detected by the developed HRM assays. G6PD genotyping revealed a total of 12 G6PD genotypes, with a high prevalence of intronic variants. Our results suggested that HRM analysis-based genotyping is a simple and reliable approach for detecting G6PD mutations, and could be used to prevent the misdiagnosis of heterozygous females by phenotypic assay. This study also sheds light on the possibility of overlooking intronic variants, which could affect G6PD expression and contribute to enzyme deficiency.

Readthrough Approach Using NV Translational Readthrough-Inducing Drugs (TRIDs): A Study of the Possible Off-Target Effects on Natural Termination Codons (NTCs) on TP53 and Housekeeping Gene Expression

Nonsense mutations cause several genetic diseases such as cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman-Diamond syndrome. These mutations induce the formation of a premature termination codon (PTC) inside the mRNA sequence, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named "translational readthrough" and restore the synthesis of full-length and potentially functional proteins. The new oxadiazole-core TRIDs NV848, NV914, and NV930 (NV) showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecule treatment induces NTC readthrough: (1) a study of the translational-induced p53 molecular weight and functionality; (2) the evaluation of two housekeeping proteins' (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 did not induce any translation alterations in both experimental systems. The data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs.

A-to-I RNA editing shows dramatic up-regulation in osteosarcoma and broadly regulates tumor-related genes by altering microRNA target regions

A-to-I RNA editing is a prevalent type of RNA modification in animals. The dysregulation of RNA editing has led to multiple human cancers. However, the role of RNA editing has never been studied in osteosarcoma, a complex bone cancer with unknown molecular basis. We retrieved the RNA-sequencing data from 24 primary osteosarcoma patients and 3 healthy controls. We systematically profiled the RNA editomes in these samples and quantitatively identified reliable differential editing sites (DES) between osteosarcoma and normal samples. RNA editing efficiency is dramatically increased in osteosarcoma, presumably due to the significant up-regulation of editing enzymes ADAR1 and ADAR2. Up-regulated DES in osteosarcoma are enriched in 3'UTRs. Strikingly, such 3'UTR sites are further enriched in microRNA binding regions of gene EMP2 and other oncogenes, abolishing the microRNA suppression on target genes. Accordingly, the expression of these tumor-promoting genes is elevated in osteosarcoma. There might be an RNA editing-dependent pathway leading to osteosarcoma. We expanded our knowledge on the potential roles of RNA editing in oncogenesis. Based on these molecular features, our work is valuable for future prognosis and diagnosis of osteosarcoma.

Commonalities and differences in the mutational signature and somatic driver mutation landscape across solid and hollow viscus organs

Advances in sequencing have revealed a highly variegated landscape of mutational signatures and somatic driver mutations in a range of normal tissues. Normal tissues accumulate mutations at varying rates ranging from 11 per cell per year in the liver, to 1879 per cell per year in the bladder. In addition, some normal tissues are also comprised of a large proportion of cells which possess driver mutations while appearing phenotypically normal, as in the oesophagus where a majority of cells harbour driver mutations. Individual tissue proliferation and mutation rate, unique mutagenic stimuli, and local tissue architecture contribute to this highly variegated landscape which confounds the functional characterization of driver mutations found in normal tissue. In particular, our understanding of the relationship between normal tissue somatic mutations and tumour initiation or future cancer risk remains poor. Here, we describe the mutational signatures and somatic driver mutations in solid and hollow viscus organs, highlighting unique characteristics in a tissue-specific manner, while simultaneously seeking to describe commonalities which can bring forward a basic unified theory on the role of these driver mutations in tumour initiation. We discuss novel findings which can be used to inform future research in this field.

Identification of differentially expressed genes and SNPs linked to harvest body weight of genetically improved rohu carp, Labeo rohita

In most of the aquaculture selection programs, harvest body weight has been a preferred performance trait for improvement. Molecular interplay of genes linked to higher body weight is not elucidated in major carp species. The genetically improved rohu carp with 18% average genetic gain per generation with respect to harvest body weight is a promising candidate for studying genes' underlying performance traits. In the present study, muscle transcriptome sequencing of two groups of individuals, with significant difference in breeding value, belonging to the tenth generation of rohu carp was performed using the Illumina HiSeq 2000 platform. A total of 178 million paired-end raw reads were generated to give rise to 173 million reads after quality control and trimming. The genome-guided transcriptome assembly and differential gene expression produced 11,86,119 transcripts and 451 upregulated and 181 downregulated differentially expressed genes (DEGs) between high-breeding value and low-breeding value (HB & LB) groups, respectively. Similarly, 39,158 high-quality coding SNPs were identified with the Ts/Tv ratio of 1.23. Out of a total of 17 qPCR-validated transcripts, eight were associated with cellular growth and proliferation and harbored 13 SNPs. The gene expression pattern was observed to be positively correlated with RNA-seq data for genes such as myogenic factor 6, titin isoform X11, IGF-1 like, acetyl-CoA, and thyroid receptor hormone beta. A total of 26 miRNA target interactions were also identified to be associated with significant DETs (p-value < 0.05). Genes such as Myo6, IGF-1-like, and acetyl-CoA linked to higher harvest body weight may serve as candidate genes in marker-assisted breeding and SNP array construction for genome-wide association studies and genomic selection.

Synonymous and Nonsynonymous Substitutions in Dictyostelium discoideum Ammonium Transporter amtA Are Necessary for Functional Complementation in Saccharomyces cerevisiae

Ammonium transporters are present in all three domains of life. They have undergone extensive horizontal gene transfer (HGT), gene duplication, and functional diversification and therefore offer an excellent paradigm to study protein evolution. We attempted to complement a mep1Δmep2Δmep3Δ strain of Saccharomyces cerevisiae (triple-deletion strain), which otherwise cannot grow on ammonium as a sole nitrogen source at concentrations of <3 mM, with amtA of Dictyostelium discoideum, an orthologue of S. cerevisiae MEP2. We observed that amtA did not complement the triple-deletion strain of S. cerevisiae for growth on low-ammonium medium. We isolated two mutant derivatives of amtA (amtA M1 and amtA M2) from a PCR-generated mutant plasmid library that complemented the triple-deletion strain of S. cerevisiae. amtA M1 bears three nonsynonymous and two synonymous substitutions, which are necessary for its functionality. amtA M2 bears two nonsynonymous substitutions and one synonymous substitution, all of which are necessary for functionality. Interestingly, AmtA M1 transports ammonium but does not confer methylamine toxicity, while AmtA M2 transports ammonium and confers methylamine toxicity, demonstrating functional diversification. Preliminary biochemical analyses indicated that the mutants differ in their conformations as well as their mechanisms of ammonium transport. These intriguing results clearly point out that protein evolution cannot be fathomed by studying nonsynonymous and synonymous substitutions in isolation. The above-described observations have significant implications for various facets of biological processes and are discussed in detail. IMPORTANCE Functional diversification following gene duplication is one of the major driving forces of protein evolution. While the role of nonsynonymous substitutions in the functional diversification of proteins is well recognized, knowledge of the role of synonymous substitutions in protein evolution is in its infancy. Using functional complementation, we isolated two functional alleles of the D. discoideum ammonium transporter gene (amtA), which otherwise does not function in S. cerevisiae as an ammonium transporters. One of them is an ammonium transporter, while the other is an ammonium transporter that also confers methylammonium (ammonium analogue) toxicity, suggesting functional diversification. Surprisingly, both alleles require a combination of synonymous and nonsynonymous substitutions for their functionality. These results bring out a hitherto-unknown pathway of protein evolution and pave the way for not only understanding protein evolution but also interpreting single nucleotide polymorphisms (SNPs).

Genome-wide sequencing identifies a thermal-tolerance related synonymous mutation in the mussel, Mytilisepta virgata

The roles of synonymous mutations for adapting to stressful thermal environments are of fundamental biological and ecological interests but poorly understood. To study whether synonymous mutations influence thermal adaptation at specific microhabitats, a genome-wide genotype-phenotype association analysis is carried out in the black mussels Mytilisepta virgata. A synonymous mutation of Ubiquitin-specific Peptidase 15 (MvUSP15) is significantly associated with the physiological upper thermal limit. The individuals carrying GG genotype (the G-type) at the mutant locus possess significantly lower heat tolerance compared to the individuals carrying GA and AA genotypes (the A-type). When heated to sublethal temperature, the G-type exhibit higher inter-individual variations in MvUSP15 expression, especially for the mussels on the sun-exposed microhabitats. Taken together, a synonymous mutation in MvUSP15 can affect the gene expression profile and interact with microhabitat heterogeneity to influence thermal resistance. This integrative study sheds light on the ecological importance of adaptive synonymous mutations as an underappreciated genetic buffer against heat stress and emphasizes the importance of integrative studies at a microhabitat scale for evaluating and predicting the impacts of climate change.

Molecular and Developmental Signatures of Genital Size Macro-Evolution in Bugs

Our understanding of the genetic architecture of phenotypic traits has experienced drastic growth over the last years. Nevertheless, the majority of studies associating genotypes and phenotypes have been conducted at the ontogenetic level. Thus, we still have an elusive knowledge of how these genetic-developmental architectures evolve themselves and how their evolution is mirrored in the phenotypic change across evolutionary time. We tackle this gap by reconstructing the evolution of male genital size, one of the most complex traits in insects, together with its underlying genetic architecture. Using the order Hemiptera as a model, spanning over 350 million years of evolution, we estimate the correlation between genitalia and three features: development rate, body size, and rates of DNA substitution in 68 genes associated with genital development. We demonstrate that genital size macro-evolution has been largely dependent on body size and weakly influenced by development rate and phylogenetic history. We further revealed significant correlations between mutation rates and genital size for 19 genes. Interestingly, these genes have diverse functions and participate in distinct signaling pathways, suggesting that genital size is a complex trait whose fast evolution has been enabled by molecular changes associated with diverse morphogenetic processes. Our data further demonstrate that the majority of DNA evolution correlated with the genitalia has been shaped by negative selection or neutral evolution. Thus, in terms of sequence evolution, changes in genital size are predominantly facilitated by relaxation of constraints rather than positive selection, possibly due to the high pleiotropic nature of the morphogenetic genes.

The Sponge Interaction Between Circular RNA and microRNA Serves as a Fast-Evolving Mechanism That Suppresses Non-small Cell Lung Cancer (NSCLC) in Humans

Non-small cell lung cancer (NSCLC) is one of the most lethal cancer types in the world. Currently, the molecular mechanisms and pathways underlying NSCLC oncogenesis are poorly understood. Using multiple Omics data, we systematically explored the differentially expressed circular RNAs (circRNAs) in NSCLC. We also investigated potential microRNA sponges (that absorb circRNAs) in NSCLC and downstream target genes with experimental verifications. hsa_circ_0003497 was down-regulated in NSCLC and played an inhibitory role in tumorigenesis. In contrast, miR-197-3p was up-regulated in NSCLC. hsa_circ_0003497 directly interacts with miR-197-3p and releases a target gene of miR-197-3p termed CTNND1 (a known tumor suppressor gene). Evolutionary analysis reveals fast evolution of this hsa_circ_0003497-miR-197-3p-CTNND1-NSCLC axis in mammals. This work clarified the biological functions and molecular mechanisms of how hsa_circ_0003497 suppresses NSCLC through miR-197-3p and CTNND1. We discovered molecular markers for the prognosis of NSCLC and provided potential intervention targets for its treatment.

Codon Usage is Influenced by Compositional Constraints in Genes Associated with Dementia

Dementia is a clinical syndrome characterized by progressive cognitive decline, and the symptoms could be gradual, persistent, and progressive. In the present study, we investigated 47 genes that have been linked to dementia. Compositional, selectional, and mutational forces were seen to be involved. Nucleotide components that influenced A- and GC-affected codon usages bias at all three codon positions. The influence of these two compositional constraints on codon usage bias (CUB) was positive for nucleotide A and negative for GC. Nucleotide A also experienced the highest mutational force, and GC-ending codons were preferred over AT-ending codons. A high bias toward GC-ending codons enhances the gene expression level, evidenced by the positive association between CAI- and GC-ending codons. Unusual behavior of the TTG codon showing an inverse relationship with the GC-ending codon and negative influence of gene expression, behavior contrary to all other GC-ending codons, shows an operative selectional force. Furthermore, parity analysis, higher translational selection value, preference of GC-ending codons over AT-ending codons, and association of gene length with gene expression refer to the dominant role of selection pressure with compositional constraint and mutational force-shaping codon usage.

The MitoAging Project: Single nucleotide polymorphisms (SNPs) in mitochondrial genes and their association to longevity

Mitochondrial dysfunction is a major hallmark of aging. Mitochondrial DNA (mtDNA) mutations (inherited or acquired) may cause a malfunction of the respiratory chain (RC), and thus negatively affect cell metabolism and function. In contrast, certain mtDNA single nucleotide polymorphisms (SNPs) may be beneficial to mitochondrial electron transport chain function and the extension of cellular health as well as lifespan. The goal of the MitoAging project is to detect key physiological characteristics and mechanisms that improve mitochondrial function and use them to develop therapies to increase longevity and a healthy lifespan. We chose to perform a systematic literature review (SLR) as a tool to collect key mtDNA SNPs associated with an increase in lifespan. Then validated our results by comparing them to the MitoMap database. Next, we assessed the effect of relevant SNPs on protein stability. A total of 28 SNPs were found in protein coding regions. These SNPs were reported in Japan, China, Turkey, and India. Among the studied SNPs, the C5178A mutation in the ND2 gene of Complex I of the RC was detected in all the reviewed reports except in Uygur Chinese centenarians. Then, we found that G9055A (ATP6 gene) and A10398G (ND3 gene) polymorphisms have been associated with a protective effect against Parkinson's disease (PD). Additionally, C8414T in ATP8 was significantly associated with longevity in three Japanese reports. Interestingly, using MitoMap we found that G9055A (ATP6 gene) was the only SNP promoting longevity not associated with any pathology. The identification of SNPs associated with an increase in lifespan opens the possibility to better understand individual differences regarding a decrease in illness susceptibility and find strategies that contribute to healthy aging.

Code inside the codon: The role of synonymous mutations in regulating splicing machinery and its impact on disease

In eukaryotes, precise pre-mRNA processing, including alternative splicing, is essential to carry out the intricate protein translation process. Both point mutations (that alter the translated protein sequence) and synonymous mutations (that do not alter the translated protein sequence) are capable of affecting the splicing process. Synonymous mutations are known to affect gene expression via altering mRNA stability, mRNA secondary structure, splicing processes, and translational kinetics. In higher eukaryotes, precise splicing is regulated by three weakly conserved cis-elements, 5' and 3' splice sites and the branch site. Many other cis-acting elements (exonic/intronic splicing enhancers and silencers) and trans-acting splicing factors (serine and arginine-rich proteins and heterogeneous nuclear ribonucleoproteins) have also been found to enhance or suppress the splicing process. The appearance of synonymous mutations in cis-acting elements can alter the splicing process by changing the binding pattern of splicing factors to exonic splicing enhancers or silencer motifs. This results in exon skipping, intron retention, and various other forms of alternative splicing, eventually leading to the emergence of a wide range of diseases. The focus of this review is to elucidate the role of synonymous mutations and their impact on abnormal splicing mechanisms. Further, this study highlights the function of synonymous mutation in mediating abnormal splicing in cancer and development of X-linked, and autosomal inherited diseases.

Mutation load in sunflower inversions is negatively correlated with inversion heterozygosity

Recombination is critical both for accelerating adaptation and purging deleterious mutations. Chromosomal inversions can act as recombination modifiers that suppress local recombination in heterozygotes and thus, under some conditions, are predicted to accumulate such mutations. In this study, we investigated patterns of recombination, transposable element abundance and coding sequence evolution across the genomes of 1,445 individuals from three sunflower species, as well as within nine inversions segregating within species. We also analyzed the effects of inversion genotypes on 87 phenotypic traits to test for overdominance. We found significant negative correlations of long terminal repeat retrotransposon abundance and deleterious mutations with recombination rates across the genome in all three species. However, we failed to detect an increase in these features in the inversions, except for a modest increase in the proportion of stop codon mutations in several very large or rare inversions. Consistent with this finding, there was little evidence of overdominance of inversions in phenotypes that may relate to fitness. On the other hand, significantly greater load was observed for inversions in populations polymorphic for a given inversion compared to populations monomorphic for one of the arrangements, suggesting that the local state of inversion polymorphism affects deleterious load. These seemingly contradictory results can be explained by the low frequency of inversion heterozygotes in wild sunflower populations, apparently due to divergent selection and associated geographic structure. Inversions contributing to local adaptation represent ideal recombination modifiers, acting to facilitate adaptive divergence with gene flow, while largely escaping the accumulation of deleterious mutations.

Synonymous Variants: Necessary Nuance in our Understanding of Cancer Drivers and Treatment Outcomes

Once called "silent mutations" and assumed to have no effect on protein structure and function, synonymous variants are now recognized to be drivers for some cancers. There have been significant advances in our understanding of the numerous mechanisms by which synonymous single nucleotide variants (sSNVs) can affect protein structure and function by affecting pre-mRNA splicing, mRNA expression, stability, folding, miRNA binding, translation kinetics, and co-translational folding. This review highlights the need for considering sSNVs in cancer biology to gain a better understanding of the genetic determinants of human cancers and to improve their diagnosis and treatment. We surveyed the literature for reports of sSNVs in cancer and found numerous studies on the consequences of sSNVs on gene function with supporting in vitro evidence. We also found reports of sSNVs that have statistically significant associations with specific cancer types but for which in vitro studies are lacking to support the reported associations. Additionally, we found reports of germline and somatic sSNVs that were observed in numerous clinical studies and for which in silico analysis predicts possible effects on gene function. We provide a review of these investigations and discuss necessary future studies to elucidate the mechanisms by which sSNVs disrupt protein function and are play a role in tumorigeneses, cancer progression, and treatment efficacy. As splicing dysregulation is one of the most well recognized mechanisms by which sSNVs impact protein function, we also include our own in silico analysis for predicting which sSNVs may disrupt pre-mRNA splicing.

Mutations in Growth-Related Genes Induced by EMS Treatment in Scallops

Background: The goal of genetic breeding is to select variants with mutations that are related to expected traits, such as fast growth. Artificial induction has been widely used to obtain strains with more mutations for further selection. Ethylmethylsulfone (EMS) is one of the most commonly used chemical mutagens in plant and microorganism breeding. However, the application of EMS mutagenesis in shellfish has not been reported. The aim of this study is to evaluate the potential use of EMS as a mutagen in scallop breeding, especially in characterization of mutations in growth-related genes. Results: Our results indicated that hatching of about 50% of fertilized eggs was blocked by treatment with 20 mM EMS for 3 h and the resulted larvae developed normally into adult stages. We then evaluated the mutagenic effects of EMS by sequencing the genomes of 4 adult scallops from the control group and 12 from the treatment group at 8 months after fertilization. On average, after removing shared types of mutations, there were 1,151,380 ± 258,188 SNPs (Single Nucleotide Polymorphisms) and 229,256 ± 51,714 InDels (insertion-deletion) in each animal in the EMS treatment group, while there were only134841 ± 10,115 SNPs and 42,605 ± 5,136 InDels in the control group. The average mutation rate in the genome of the EMS treatment group (0.0137 ± 0.0013%) was about 9 times that of the control group (0.0015 ± 0.0002%). GO (Gene Ontology) annotation and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses revealed that mutations induced by EMS occurred evenly in most biological processes, cellular components and functions, as well in most pathways. However, significant lower percentage of mutations were found in the exonic region, in non-synonymous or Stopgain/Stoploss SNPs and in coding domains, suggesting apparent DNA repair or selection during grow-out stage. Analyses of the growth-related genes with mutations indicated that mutations in MFS (Major Facilitator Superfamily) and Tubulin were only found in the large-sized group (Five largest scallops: Treated-1, Treated-2, Treated-3, Treated-4, and Treated-5) and Homeobox and Socs (Suppressor of cytokine signaling) only in the small group (Two smallest scallops: Treated-11 and Treated-12). These results suggested that these genes may be involved in the regulation of growth in these animals, although further verification is certainly warranted. Conclusion: Treatment of fertilized eggs with 20 mM EMS for 3 h induced 9 times more mutations in scallop genomes. We found that mutations in MFS and Tubulin may be related to fast growth in the large-sized group and those mutations in Homeobox and SOCs may be involved in the slow growth in the small-sized scallops. EMS can be used to accelerate selection of economically important traits in molluscs.

Identification of SSTR5 Gene Polymorphisms and Their Association With Growth Traits in Hulun Buir Sheep

The aim of this study was to locate SSTR5 polymorphisms and evaluate their association with growth traits in Hulun Buir sheep. The study followed up 884 Hulun Buir sheep from birth to 16 months of age, which were born in the same pasture and the same year, and a consistent grazing management strategy was maintained. The birth weight (BRW) was recorded at birth, and body weight (BW), body height (BH), body length (BL), chest circumference (ChC), chest depth (ChD), chest width (ChW), hip width (HW), and cannon circumference (CaC) were measured at 4 and 9 months of age. BW, BH, BL, ChD, HW, and CaC were also recorded at 16 months of age. Based on the growth traits, 233 sheep were selected as experimental animals. Sanger sequencing was performed, and seven single-nucleotide polymorphisms (SNPs) were identified. Association analyses of the SNPs and the growth traits were then conducted. Seven SNPs of the SSTR5 exhibited moderate polymorphism (0.25 Collapse

Key Words

• Hulun Buir sheep
• SSTR5
• association
• growth traits
• haplotypes

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Affiliation(s)

Xue Li Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China University of Chinese Academy of Sciences, Beijing, China
Ning Ding Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China University of Chinese Academy of Sciences, Beijing, China
Zhichao Zhang Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China University of Chinese Academy of Sciences, Beijing, China
Dehong Tian Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
Buying Han Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China University of Chinese Academy of Sciences, Beijing, China
Dehui Liu Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China University of Chinese Academy of Sciences, Beijing, China
Sijia Liu Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
Fei Tian Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
Dejun Fu Inner Mongolia Daxing 'anling Agricultural Reclamation Group Co. LTD., Hulun Buir, China
Xiaoliang Song Inner Mongolia Daxing 'anling Agricultural Reclamation Group Co. LTD., Hulun Buir, China
Kai Zhao Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China

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Genetic Polymorphisms of IGF1 and IGF1R Genes and Their Effects on Growth Traits in Hulun Buir Sheep

The identification of candidate genes and genetic variations associated with growth traits is important for sheep breeding. Insulin like growth factor 1 (IGF1) and insulin like growth factor 1 receptor (IGF1R) are well-accepted candidate genes that affect animal growth and development. The current study attempted to assess the association between IGF1 and IGF1R genetic polymorphisms and growth traits in Hulun Buir sheep. To achieve this goal, we first identified three and ten single nucleotide polymorphisms (SNPs) in exons of IGF1 and IGF1R in Hulun Buir sheep and then constructed six haplotypes of IGF1R based on linkage disequilibrium, respectively. Association studies were performed between SNPs and haplotypes of IGF1 and IGF1R with twelve growth traits in a population encompassing 229 Hulun Buir sheep using a general linear model. Our result indicated three SNPs in IGF1 were significantly associated with four growth traits (p < 0.05). In IGF1R, three SNPs and two haplotype blocks were significantly associated with twelve growth traits (p < 0.05). The combined haplotype H5H5 and H5H6 in IGF1R showed the strong association with 12 superior growth traits in Hulun Buir sheep (p < 0.05). In conclusion, we identified SNPs and haplotype combinations associated with the growth traits, which provided genetic resources for marker-assisted selection (MAS) in Hulun Buir sheep breeding.

NELL-1 in Genome-Wide Association Studies across Human Diseases

Neural epidermal growth factor-like (EGFL)-like protein (NELL)-1 is a potent and key osteogenic factor in the development and regeneration of skeletal tissues. Intriguingly, accumulative data from genome-wide association studies (GWASs) have started unveiling potential broader roles of NELL-1 beyond its functions in bone and cartilage. With exploration of the genetic variants of the entire genome in large-scale disease cohorts, GWASs have been used for establishing the connection between specific single-nucleotide polymorphisms of NELL1, in addition to osteoporosis, metabolic diseases, inflammatory conditions, neuropsychiatric diseases, neurodegenerative disorders, and malignant tumors. This review summarizes the findings from GWASs on the manifestation, significance level, implications on function, and correlation of specific NELL1 single-nucleotide polymorphisms in various disorders in humans. By offering a unique and comprehensive correlation between genetic variants and plausible functions of NELL1 in GWASs, this review illustrates the wide range of potential effects of a single gene on the pathogenesis of multiple disorders in humans.

Identification of genotypic variants and its proteomic mutations of Brazilian SARS-CoV-2 isolates

The second wave of COVID-19 caused by severe acute respiratory syndrome virus (SARS-CoV-2) is rapidly spreading over the world. Mechanisms behind the flee from current antivirals are still unclear due to the continuous occurrence of SARS-CoV-2 genetic variants. Brazil is the world's second-most COVID-19 affected country. In the present study, we identified the genomic and proteomic variants of Brazilian SARS-CoV-2 isolates. We identified 16 different genotypic variants were found among the 27 isolates. The genotypes of three isolates such as Bra/1236/2021 (G15), Bra/MASP2C844R2/2020 (G11), and Bra/RJ-DCVN5/2020 (G9) have a unique mutant in NSP4 (S184N), 2′O-Mutase (R216N), membrane protein (A2V) and Envelope protein (V5A). A mutation in RdRp of SARS-CoV-2, particularly the change of Pro-to Leu-at 323 resulted in the stabilization of the structure in BRA/CD1739-P4/2020. NSP4, NSP5 protein mutants are more virulent in genotype 15 and 16. A fast protein folding rate changes the structural stability and leads to escape for current antivirals. Thus, our findings help researchers to develop the best potent antivirals based on the new mutant of Brazilian isolates.

Identification of Somatostatin Receptor Subtype 1 (SSTR1) Gene Polymorphism and Their Association with Growth Traits in Hulun Buir Sheep

This study was conducted to evaluate SSTR1 gene polymorphisms and their association with growth traits in Hulun Buir sheep. We followed 233 Hulun Buir sheep from birth to 16 months of age, born in the same pasture and on the same year under a consistent grazing conditions. The body weight (BW), body height (BH), body length (BL), chest circumference (ChC), chest depth (ChD), chest width (ChW), hip width (HW), and cannon circumference (CaC) were measured and recorded at birth, 4 months, 9 months, and 16 months of age. The polymorphisms of the SSTR1 gene in Hulun Buir sheep were excavated using exon sequencing, and association analyses of between SNPs and growth traits at each growth stage were conducted. The results showed that there were four SNPs in Exon 2 of the SSTR1 gene, SNP1, SNP2, and SNP3 were low mutation sites, and SNP4 was a moderate mutation site. Four SNPs were consistent with Hardy–Weinberg equilibrium, and all of them were synonymous mutations. The association analyses found that the genotypes of SNP2 were significantly associated with WW and BH at 4 months of age, BW, BL, ChC, and HW at 9 months of age (p < 0.05), and extremely significantly associated with ChD at 4 and 9 months of age (p < 0.01). There were significant associations between SNP3 and BH at 9 months of age, between SNP4 and ChD, ChW, and CaC at 9 months of age, and BW and ChC at 16 months of age (p < 0.05). There were no detectable associations with growth traits among the seven haplotypes between the SNP1, 3, and 4 of a strong linkage disequilibrium (p > 0.05). These results indicated that SNP2, SNP3, and SNP4 may be used as molecular markers for growth traits of Hulun Buir sheep.

Unexpected myriad of co-occurring viral strains and species in one of the most abundant and microdiverse viruses on Earth

Viral genetic microdiversity drives adaptation, pathogenicity, and speciation and has critical consequences for the viral-host arms race occurring at the strain and species levels, which ultimately impact microbial community structure and biogeochemical cycles. Despite the fact that most efforts have focused on viral macrodiversity, little is known about the microdiversity of ecologically important viruses on Earth. Recently, single-virus genomics discovered the putatively most abundant ocean virus in temperate and tropical waters: the uncultured dsDNA virus vSAG 37-F6 infecting Pelagibacter, the most abundant marine bacteria. In this study, we report the cooccurrence of up to ≈1,500 different viral strains (>95% nucleotide identity) and ≈30 related species (80-95% nucleotide identity) in a single oceanic sample. Viral microdiversity was maintained over space and time, and most alleles were the result of synonymous mutations without any apparent adaptive benefits to cope with host translation codon bias and efficiency. Gene flow analysis used to delimitate species according to the biological species concept (BSC) revealed the impact of recombination in shaping vSAG 37-F6 virus and Pelagibacter speciation. Data demonstrated that this large viral microdiversity somehow mirrors the host species diversity since ≈50% of the 926 analyzed Pelagibacter genomes were found to belong to independent BSC species that do not significantly engage in gene flow with one another. The host range of this evolutionarily successful virus revealed that a single viral species can infect multiple Pelagibacter BSC species, indicating that this virus crosses not only formal BSC barriers but also biomes since viral ancestors are found in freshwater.

Large-scale omics data reveal the cooperation of mutation-circRNA-miRNA-target gene network in liver cancer oncogenesis

Aims: Clarifying the initial trigger of the differentially expressed genes in cancers helps researchers understand the cellular system as a whole network. Materials & methods: We retrieve the transcriptome and translatome of tumor and normal tissues from ten liver cancer patients and define differentially expressed genes and tumor-specific mutations. We associate the oncogenesis with the mutations by target prediction and experimental verification. Results: Upregulated genes have tumor-specific mutations in 3'UTRs that abolish the binding of miRNAs. For downregulated genes, their corresponding miRNAs are mutually targeted by two circRNAs, with mutations in base-pairing regions. Transfection experiments support the oncogenic role of these mutations. Conclusions: The tumor-specific mutations serve as the initial trigger of liver cancer. The mutation-circRNA-miRNA-target gene chain is completed.

rs10865710 polymorphism in PPARG promoter is associated with the severity of type 2 diabetes mellitus and coronary artery disease in a Chinese population

BACKGROUND

Relationship between polymorphisms in peroxisome proliferator-activated receptor gamma (PPARG) and progression of type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) remains to be clarified.

METHODS

635 subjects were divided into T2DM, CAD, T2DM complicated with CAD (T2DM/CAD) and control groups according to diagnostic criteria. The rs10865710 and rs3856806 polymorphisms were genotyped, and the severity of T2DM and CAD was evaluated for all subjects.

RESULTS

In patients with T2DM, G allele carriers of rs10865710 polymorphism had significantly higher levels of glucose, triglycerides, apolipoprotein B (ApoB) and lipoprotein (a) (Lp(a)) than non-carriers, T allele carriers of rs3856806 polymorphism had significantly higher levels of glucose, low-density lipoprotein cholesterol (LDL-C), ApoB and Lp(a) than non-carriers. In patients with CAD, G allele carriers of rs10865710 polymorphism had significantly higher levels of total cholesterol (TC), ApoB and Lp(a) than non-carriers, T allele carriers of rs3856806 polymorphism had significantly higher levels of body mass index, blood pressure, TC, LDL-C and ApoB than non-carriers. Patients with one or two G alleles of rs10865710 polymorphism had significantly higher levels of Gensini scores and more diseased coronary branches than those patients without CAD. The rs3856806 polymorphism was not associated with CAD severity, but it was found to be significantly associated with T2DM/CAD, T allele frequency was significantly higher in T2DM/CAD group than that in T2DM/CAD-free group.

CONCLUSIONS

The rs10865710 and rs3856806 polymorphisms in PPARG are significantly associated with glucose levels in patients with T2DM. The rs10865710 polymorphism is significantly associated with the severity of CAD, which is possibly mediated by hyperlipidaemia and hyperglycaemia.

Identifying Cancer Drivers Using DRIVE: A Feature-Based Machine Learning Model for a Pan-Cancer Assessment of Somatic Missense Mutations

Sporadic cancer develops from the accrual of somatic mutations. Out of all small-scale somatic aberrations in coding regions, 95% are base substitutions, with 90% being missense mutations. While multiple studies focused on the importance of this mutation type, a machine learning method based on the number of protein-protein interactions (PPIs) has not been fully explored. This study aims to develop an improved computational method for driver identification, validation and evaluation (DRIVE), which is compared to other methods for assessing its performance. DRIVE aims at distinguishing between driver and passenger mutations using a feature-based learning approach comprising two levels of biological classification for a pan-cancer assessment of somatic mutations. Gene-level features include the maximum number of protein-protein interactions, the biological process and the type of post-translational modifications (PTMs) while mutation-level features are based on pathogenicity scores. Multiple supervised classification algorithms were trained on Genomics Evidence Neoplasia Information Exchange (GENIE) project data and then tested on an independent dataset from The Cancer Genome Atlas (TCGA) study. Finally, the most powerful classifier using DRIVE was evaluated on a benchmark dataset, which showed a better overall performance compared to other state-of-the-art methodologies, however, considerable care must be taken due to the reduced size of the dataset. DRIVE outlines the outstanding potential that multiple levels of a feature-based learning model will play in the future of oncology-based precision medicine.

Codon usage bias and environmental adaptation in microbial organisms

In each genome, synonymous codons are used with different frequencies; this general phenomenon is known as codon usage bias. It has been previously recognised that codon usage bias could affect the cellular fitness and might be associated with the ecology of microbial organisms. In this exploratory study, we investigated the relationship between codon usage bias, lifestyles (thermophiles vs. mesophiles; pathogenic vs. non-pathogenic; halophilic vs. non-halophilic; aerobic vs. anaerobic and facultative) and habitats (aquatic, terrestrial, host-associated, specialised, multiple) of 615 microbial organisms (544 bacteria and 71 archaea). Principal component analysis revealed that species with given phenotypic traits and living in similar environmental conditions have similar codon preferences, as represented by the relative synonymous codon usage (RSCU) index, and similar spectra of tRNA availability, as gauged by the tRNA gene copy number (tGCN). Moreover, by measuring the average tRNA adaptation index (tAI) for each genome, an index that can be associated with translational efficiency, we observed that organisms able to live in multiple habitats, including facultative organisms, mesophiles and pathogenic bacteria, are characterised by a reduced translational efficiency, consistently with their need to adapt to different environments. Our results show that synonymous codon choices might be under strong translational selection, which modulates the choice of the codons to differently match tRNA availability, depending on the organism's lifestyle needs. To our knowledge, this is the first large-scale study that examines the role of codon bias and translational efficiency in the adaptation of microbial organisms to the environment in which they live.

Context-dependent and -independent selection on synonymous mutations revealed by 1,135 genomes of Arabidopsis thaliana

BACKGROUND

Synonymous mutations do not alter the amino acids and therefore are regarded as neutral for a long time. However, they do change the tRNA adaptation index (tAI) of a particular codon (independent of its context), affecting the tRNA availability during translation. They could also change the isoaccepting relationship with its neighboring synonymous codons in particular context, which again affects the local translation process. Evidence of selection pressure on synonymous mutations has emerged.

RESULTS

The proposed selection patterns on synonymous mutations are never formally and systematically tested in plant species. We fully take advantage of the SNP data from 1,135 A. thaliana lines, and found that the synonymous mutations that increase tAI or the isoaccepting mutations in isoaccepting codon context tend to have higher derived allele frequencies (DAF) compared to other synonymous mutations of the opposite effects.

CONCLUSIONS

Synonymous mutations are not strictly neutral. The synonymous mutations that increase tAI or the isoaccepting mutations in isoaccepting codon context are likely to be positively selected. We propose the concept of context-dependent and -independent selection on synonymous mutations. These concepts broaden our knowledge of the functional consequences of synonymous mutations, and should be appealing to phytologists and evolutionary biologists.

An evolutionary approach to clonally complex hematologic disorders

Emerging clonal complexity has brought into question the way in which we perceive and, in turn, treat disorders of the hematopoietic system. Former models of cell-intrinsic clonal dominance driven by acquisition of driver genes in a stereotypic sequence are often insufficient in explaining observations such as clonal hematopoiesis, and new paradigms are in order. Here, we review the evidence both within the hematologic malignancy field and also borrow from perspectives rooted in evolutionary biology to reframe pathogenesis of hematologic disorders as dynamic processes involving complex interplays of genetic and non-genetic subclones and the tissue microenvironment in which they reside.

Retrieving the deleterious mutations before extinction: genome-wide comparison of shared derived mutations in liver cancer and normal population

STUDY PURPOSE

Deleterious mutations would be rapidly purged from natural populations along with the extinction of their carriers. The currently observed mutations in existing species are mostly neutral. The inaccessibility of deleterious mutations impedes the functional studies on how these mutations affect the fitness at individual level.

STUDY DESIGN

The connection between the deleterious genotype and the non-adaptive phenotype could be bridged by sequencing the genome before extinction. Although this approach is no longer feasible for evolutionary biologists, it is feasible for cancer biologists by profiling the mutations in tumour samples which are so deleterious that the carriers hardly live.

RESULTS

By comparing the derived mutation profile between normal populations and patients with liver cancer, we found that the shared mutations, which are highly deleterious, are suppressed to low allele frequencies in normal populations and tissues, but show remarkably high frequency in tumours. The density of shared mutations is negatively correlated with gene conservation and expression levels.

CONCLUSIONS

Deleterious mutations are suppressed in functionally important genes as well as in normal populations. This work deepened our understanding on how natural selection act on deleterious mutations by analogising the cancer evolution to species evolution, which are essentially the same molecular process but at different time scales.

Synonymous mutations that regulate translation speed might play a non-negligible role in liver cancer development

Background

Synonymous mutations do not change the protein sequences. Automatically, they have been regarded as neutral events and are ignored in the mutation-based cancer studies. However, synonymous mutations will change the codon optimality, resulting in altered translational velocity.

Methods

We fully utilized the transcriptome and translatome of liver cancer and normal tissue from ten patients. We profiled the mutation spectrum and examined the effect of synonymous mutations on translational velocity.

Results

Synonymous mutations that increase the codon optimality significantly enhanced the translational velocity, and were enriched in oncogenes. Meanwhile, synonymous mutations decreasing codon optimality slowed down translation, and were enriched in tumor suppressor genes. These synonymous mutations significantly contributed to the translational changes in tumor samples compared to normal samples.

Conclusions

Synonymous mutations might play a role in liver cancer development by altering codon optimality and translational velocity. Synonymous mutations should no longer be ignored in the genome-wide studies.

Positive epistasis between disease-causing missense mutations and silent polymorphism with effect on mRNA translation velocity

Epistasis refers to the dependence of a mutation on other mutation(s) and the genetic context in general. In the context of human disorders, epistasis complicates the spectrum of disease symptoms and has been proposed as a major contributor to variations in disease outcome. The nonadditive relationship between mutations and the lack of complete understanding of the underlying physiological effects limit our ability to predict phenotypic outcome. Here, we report positive epistasis between intragenic mutations in the cystic fibrosis transmembrane conductance regulator (CFTR)-the gene responsible for cystic fibrosis (CF) pathology. We identified a synonymous single-nucleotide polymorphism (sSNP) that is invariant for the CFTR amino acid sequence but inverts translation speed at the affected codon. This sSNP in cis exhibits positive epistatic effects on some CF disease-causing missense mutations. Individually, both mutations alter CFTR structure and function, yet when combined, they lead to enhanced protein expression and activity. The most robust effect was observed when the sSNP was present in combination with missense mutations that, along with the primary amino acid change, also alter the speed of translation at the affected codon. Functional studies revealed that synergistic alteration in ribosomal velocity is the underlying mechanism; alteration of translation speed likely increases the time window for establishing crucial domain-domain interactions that are otherwise perturbed by each individual mutation.

Effect of Genetic Variants of Gonadotropins and Their Receptors on Ovarian Stimulation Outcomes: A Delphi Consensus

BACKGROUND

A Delphi consensus was conducted to evaluate the influence of single nucleotide polymorphisms (SNPs) in genes encoding gonadotropin and gonadotropin receptors on clinical ovarian stimulation outcomes following assisted reproductive technology (ART) treatment.

METHODS

Nine experts plus two Scientific Coordinators discussed and amended statements plus supporting references proposed by the Scientific Coordinators. The statements were distributed via an online survey to 36 experts, who voted on their level of agreement or disagreement with each statement. Consensus was reached if the proportion of participants agreeing or disagreeing with a statement was >66%.

RESULTS

Eleven statements were developed, of which two statements were merged. Overall, eight statements achieved consensus and two statements did not achieve consensus. The statements reaching consensus are summarized here. (1) SNP in the follicle stimulating hormone receptor (FSHR), rs6166 (c.2039A>G, p.Asn680Ser) (N=5 statements): Ser/Ser carriers have higher basal FSH levels than Asn/Asn carriers. Ser/Ser carriers require higher amounts of gonadotropin during ovarian stimulation than Asn/Asn carriers. Ser/Ser carriers produce fewer oocytes during ovarian stimulation than Asn/Asn or Asn/Ser carriers. There is mixed evidence supporting an association between this variant and ovarian hyperstimulation syndrome. (2) SNP of FSHR, rs6165 (c.919G>A, p.Thr307Ala) (N=1 statement): Few studies suggest Thr/Thr carriers require a shorter duration of gonadotropin stimulation than Thr/Ala or Ala/Ala carriers. (3) SNP of FSHR, rs1394205 (-29G>A) (N=1 statement): Limited data in specific ethnic groups suggest that A/A allele carriers may require higher amounts of gonadotropin during ovarian stimulation and produce fewer oocytes than G/G carriers. (4) SNP of FSH β-chain (FSHB), rs10835638 (-211G>T) (N=1 statement): There is contradictory evidence supporting an association between this variant and basal FSH levels or oocyte number. (5) SNPs of luteinizing hormone β-chain (LHB) and LH/choriogonadotropin receptor (LHCGR) genes (N=1 statement): these may influence ovarian stimulation outcomes and could represent potential future targets for pharmacogenomic research in ART, although data are still very limited.

CONCLUSIONS

This Delphi consensus provides clinical perspectives from a diverse international group of experts. The consensus supports a link between some variants in gonadotropin/gonadotropin receptor genes and ovarian stimulation outcomes; however, further research is needed to clarify these findings.

Dysregulated expression of mRNA and SNP in pulmonary artery remodeling in ascites syndrome in broilers

Broiler ascites syndrome (AS), also called pulmonary artery hypertension, is a metabolic disorder that has been observed worldwide in fast-growing broilers. Pulmonary arterial remodeling is a key step in the development of AS. The precise relationship between mRNA and SNP of the pulmonary artery in regulating AS progression remains unclear. In this study, we obtained pulmonary artery tissues from broilers with AS to perform pathologic section and pathologic anatomic observation. SNP, InDel, and mRNA data analysis were carried out using GATK and ANNOVAR software to study the SNP loci of 985 previously reported genes (437 upregulated and 458 downregulated). The pathology results showed that there was a lot of yellow fluid in the abdominal cavity and pericardium, that the ascites cardiac index and hematocrit changed significantly, and that the pulmonary artery had remodeled and become thicker in the disease group. Myocardial sections showed vacuolar degeneration of myocytes and rupture of muscle fibers. In addition, ALDH7A1, IRG1, GGT5, IGSF1, DHX58, USP36, TREML2, SPAG1, CD34, and PLEKHA7 were found to be closely associated with the pathogenesis of pulmonary artery remodeling in AS progression. Taken together, our present study further illuminates the molecular mechanism of pulmonary artery remodeling underlying AS progression.

Bronchoscopic intratumoral injections of cisplatin and endostar as concomitants of standard chemotherapy to treat malignant central airway obstruction

STUDY PURPOSE

Malignant central airway obstruction (CAO) in non-small cell lung cancer (NSCLC) is associated with high morbidity and requires endobronchial palliative treatment to re-establish a free air passage. We investigate intratumoral therapy combining anti-angiogenic and cytotoxic as a feasible therapeutic modality to treat malignant CAO.

STUDY DESIGN

Ten NSCLC subjects with symptomatic malignant CAO underwent endobronchial intratumoral cisplatin and Endostar co-injection after tumour debulking next to systemic cisplatin-based chemotherapy. Injection was performed immediately after debulking surgery and was then carried out on day 2, day 6 and day 10 past systemic chemotherapy. Nine subjects of control group constantly received traditional cisplatin-based chemotherapy. Bronchoscopy, CT scanning, histology, FEV1/FVC ratio, Karnofsky performance (KPS) and shortness of breath scores were analysed to assess therapeutic efficacy.

RESULTS

All 10 subjects benefited from the intratumoral cisplatin and endostar co-injection and systemic chemotherapy combination therapy. Bronchoscopy and CT scanning analyses showed a massive airway widening after treatment. Increased KPS and reduced shortness of breath score were also observed. A substantial improvement of lung function was further confirmed by increased FEV1/FVC ratio. For subjects of control group, the improvement was moderate and obviously not as optimal as the 10 subjects with intratumoral injection.

CONCLUSIONS

We have shown that the intratumoral injection of cytotoxic cisplatin plus anti-angiogenic Endostar is an effective and safe adjuvant therapeutic option to treat malignant CAO in clinical practice. This time-staggered local and systemic treatment combination improves quality of life and clinical parameters, thus may provide a feasible therapeutic option for symptomatic CAO.

A Crosstalk on Codon Usage in Genes Associated with Leukemia

Leukemia is the outcome of aggregation of damaged white blood cells. Several genes were reported to be associated with the pathogenesis of leukemia. These genes were computationally analyzed to decipher their codon usage bias (CUB) and to identify the prime factors influencing the codon usage profile as no work was reported yet. The mean values of synonymous codon usage order (SCUO) parameter indicated low CUB of the genes. Significant positive association of SCUO with overall GC and positional GCs might signal the presence of mutational pressure. However, neutrality plot suggested the dominant role of natural selection across the genes. Along with natural selection, the role of mutation pressure was also prominent and that might be responsible for lower CUB (SCUO = 0.19) of genes. Low translational speed might permit accuracy in the process. A strong inverse relationship of translational rate was observed with CUB of genes and folding energy.

Systematic analysis reveals cis and trans determinants affecting C-to-U RNA editing in Arabidopsis thaliana

Background

C-to-U RNA editing is prevalent in the mitochondrial and chloroplast genes in plants. The biological functions of a fraction of C-to-U editing sites are continuously discovered by case studies. However, at genome-wide level, the cis and trans determinants affecting the occurrence or editing levels of these C-to-U events are relatively less studied. What is known is that the PPR (pentatricopeptide repeat) proteins are the main trans-regulatory elements responsible for the C-to-U conversion, but other determinants especially the cis-regulatory elements remain largely uninvestigated.

Results

By analyzing the transcriptome and translatome data in Arabidopsis thaliana roots and shoots, combined with RNA-seq data from hybrids of Arabidopsis thaliana and Arabidopsis lyrata, we perform genome-wide investigation on the cis elements and trans-regulatory elements that potentially affect C-to-U editing events. An upstream guanosine or double-stranded RNA (dsRNA) regions are unfavorable for editing events. Meanwhile, many genes including the transcription factors may indirectly play regulatory roles in trans.

Conclusions

The 5-prime thymidine facilitates editing and dsRNA structures prevent editing in cis. Many transcription factors affect editing in trans. Although the detailed molecular mechanisms underlying the cis and trans regulation remain to be experimentally verified, our findings provide novel aspects in studying the botanical C-to-U RNA editing events.

Comparative Analysis of the Transcriptome and Distribution of Putative SNPs in Two Rainbow Trout (Oncorhynchus mykiss) Breeding Strains by Using Next-Generation Sequencing

Selective breeding can significantly improve the establishment of sustainable and profitable aquaculture fish farming. For rainbow trout (Oncorhynchus mykiss), one of the main aquaculture coldwater species in Europe, a variety of selected hatchery strains are commercially available. In this study, we investigated the genetic variation between the local Born strain, selected for survival, and the commercially available Silver Steelhead strain, selected for growth. We sequenced the transcriptome of six tissues (gills, head kidney, heart, liver, spleen, and white muscle) from eight healthy individuals per strain, using RNA-seq technology to identify strain-specific gene-expression patterns and single nucleotide polymorphisms (SNPs). In total, 1760 annotated genes were differentially expressed across all tissues. Pathway analysis assigned them to different gene networks. We also identified a set of SNPs, which are heterozygous for one of the two breeding strains: 1229 of which represent polymorphisms over all tissues and individuals. Our data indicate a strong genetic differentiation between Born and Silver Steelhead trout, despite the relatively short time of evolutionary separation of the two breeding strains. The results most likely reflect their specifically adapted genotypes and might contribute to the understanding of differences regarding their robustness toward high stress and pathogenic challenge described in former studies.

AT-rich Interaction Domain 1A Gene Variations: Genetic Associations and Susceptibility to Gastric Cancer Risk

AT-rich interaction domain containing protein 1A (ARID1A), has recently emerged as a novel class of gene which acts as a potent tumor suppressor in numerous types of cancers such as Gastric, Breast, Ovarian, Colorectal, Lung cancers. ARID1A is involved in the regulation of various cellular processes such as proliferation, differentiation and DNA repair, yet its association with the susceptibility of cancer remains unknown. Here, we aimed to analyse the association of the ARID1A variants (Pro912Thr, Gln944Lys and Gln920Ter) with the risk of Gastric cancer (GC) in Kashmiri population. The study included 103 confirmed cases of GC and 163 normal controls. The genotypes were studied using Polymerase Chain Reaction. Different bioinformatic predictive tools were also used to analyse the possible effect of these SNP's on the resultant protein. The Pro912Thr and Gln920Ter variants of ARID1A showed significant difference in genotypic and allelic frequencies between the GC cases and controls (P < 0.05), whereas, the data did not reveal any correlation between Gln944Lys variant and Gastric cancer risk. Both Pro912Thr and Gln920Ter SNP's follow "Dominant mode of inheritance". In Silico analysis predicted that amino acid substitution of Pro912Thr SNP decreases the protein stability thus changing the functional properties of resultant protein, so backing the possibility of damaging effect of this SNP. Our study suggests that Pro912Thr and Gln920Ter SNP's of ARD1A gene are associated with increased risk of GC in Kashmiri population.