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Canadian Journal of Microbiology Jun 2024The number of copies of each chromosome, or ploidy, of an organism is a major genomic factor affecting adaptation. We set out to determine how ploidy can impact the...
The number of copies of each chromosome, or ploidy, of an organism is a major genomic factor affecting adaptation. We set out to determine how ploidy can impact the outcome of evolution, as well as the likelihood of evolutionary rescue, using short-term experiments with yeast (Saccharomyces cerevisiae) in a high concentration of the fungicide nystatin. In similar experiments using haploid yeast, the genetic changes underlying evolutionary rescue were highly repeatable, with all rescued lines containing a single mutation in the ergosterol biosynthetic pathway. All of these beneficial mutations were recessive, which led to the expectation that diploids would find alternative genetic routes to adaptation. To test this, we repeated the experiment using both haploid and diploid strains and found that diploid populations did not evolve resistance. Although diploids are able to adapt at the same rate as haploids to a lower, not fully inhibitory, concentration of nystatin, the present study suggests that diploids are limited in their ability to adapt to an inhibitory concentration of nystatin, while haploids may undergo evolutionary rescue. These results demonstrate that ploidy can tip the balance between adaptation and extinction when organisms face an extreme environmental change.
PubMed: 38875715
DOI: 10.1139/cjm-2023-0235 -
Europace : European Pacing,... Jun 2024Patients with mutations in SCN5A encoding NaV1.5 often display variable severity of electrical and structural alterations, but the underlying mechanisms are not fully...
AIMS
Patients with mutations in SCN5A encoding NaV1.5 often display variable severity of electrical and structural alterations, but the underlying mechanisms are not fully elucidated. We here investigate the combined modulatory effect of genetic background and age on disease severity in the Scn5a1798insD/+ mouse model.
METHODS AND RESULTS
In vivo electrocardiogram and echocardiograms, ex vivo electrical and optical mapping, and histological analyses were performed in adult (2-7 months) and aged (8-28 months) wild-type (WT) and Scn5a1798insD/+ (mutant, MUT) mice from the FVB/N and 129P2 inbred strains. Atrio-ventricular (AV) conduction, ventricular conduction, and ventricular repolarization are modulated by strain, genotype, and age. An aging effect was present in MUT mice, with aged MUT mice of both strains showing prolonged QRS interval and right ventricular (RV) conduction slowing. 129P2-MUT mice were severely affected, with adult and aged 129P2-MUT mice displaying AV and ventricular conduction slowing, prolonged repolarization, and spontaneous arrhythmias. In addition, the 129P2 strain appeared particularly susceptible to age-dependent electrical, functional, and structural alterations including RV conduction slowing, reduced left ventricular (LV) ejection fraction, RV dilatation, and myocardial fibrosis as compared to FVB/N mice. Overall, aged 129P2-MUT mice displayed the most severe conduction defects, RV dilatation, and myocardial fibrosis, in addition to the highest frequency of spontaneous arrhythmia and inducible arrhythmias.
CONCLUSION
Genetic background and age both modulate disease severity in Scn5a1798insD/+ mice and hence may explain, at least in part, the variable disease expressivity observed in patients with SCN5A mutations. Age- and genetic background-dependent development of cardiac structural alterations furthermore impacts arrhythmia risk. Our findings therefore emphasize the importance of continued assessment of cardiac structure and function in patients carrying SCN5A mutations.
Topics: Animals; NAV1.5 Voltage-Gated Sodium Channel; Arrhythmias, Cardiac; Genetic Predisposition to Disease; Age Factors; Disease Models, Animal; Fibrosis; Mutation; Severity of Illness Index; Heart Conduction System; Action Potentials; Electrocardiography; Phenotype; Genetic Background; Mice, 129 Strain; Male; Heart Rate; Myocardium; Aging
PubMed: 38875491
DOI: 10.1093/europace/euae153 -
Heliyon Jun 2024To delve into the expression and functions of FGF2 in patient with thyroid cancer (THCA), we conducted a systematic analysis of the association of FGF2 with immune cell...
To delve into the expression and functions of FGF2 in patient with thyroid cancer (THCA), we conducted a systematic analysis of the association of FGF2 with immune cell infiltration, and prognosis in THCA patients. The transcription and protein levels, methylation, and biological properties of FGF2 were examined, along with its correlation with prognosis and immune cell infiltration in THCA patients using online databases UALCAN, Human Protein Atlas, Kaplan-Meier Plotter, DNMIVD, cBioPortal, GEPIA, Metascape, Linkedomics and TIMER. Clinical samples were collected for Western blot analyses. FGF2 was substantially overexpressed in the tumor group and shown correlations with age, tumor histology, nodal metastasis, and cancer stages. Moreover, higher expression of FGF2 = = was greatly correlated with poorer relapse-free survival in THCA patients, particularly in female patients. FGF2 methylation level was increased in the tumor group = , and higher methylation levels of FGF2 were positively correlated with the poorer progression-free interval in THCA patients = 5). FGF2 mutations were markedly associated with shorter disease-free survival, with a mutation rate of 6 % among the total 498 THCA patients. FGF2 functions were potentially related to cell adhesion, cytokine-cytokine receptor interaction and angiogenesis. FGF2 expression showed positive correlations with the infiltration of B cells , CD4 T cells , macrophages , neutrophils and dendritic cells . FGF2 is a potential prognostic marker in THCA patients, with its functions possibly related to cell adhesion, interaction of the cytokine-cytokine receptor, angiogenesis, and the promotion of multiple immune cell infiltration.
PubMed: 38873667
DOI: 10.1016/j.heliyon.2024.e32272 -
BMC Genomics Jun 2024Molluscan mitochondrial genomes are unusual because they show wide variation in size, radical genome rearrangements and frequently show high variation (> 10%) within...
Molluscan mitochondrial genomes are unusual because they show wide variation in size, radical genome rearrangements and frequently show high variation (> 10%) within species. As progress in understanding this variation has been limited, we used whole genome sequencing of a six-generation matriline of the terrestrial snail Cepaea nemoralis, as well as whole genome sequences from wild-collected C. nemoralis, the sister species C. hortensis, and multiple other snail species to explore the origins of mitochondrial DNA (mtDNA) variation. The main finding is that a high rate of SNP heteroplasmy in somatic tissue was negatively correlated with mtDNA copy number in both Cepaea species. In individuals with under ten mtDNA copies per nuclear genome, more than 10% of all positions were heteroplasmic, with evidence for transmission of this heteroplasmy through the germline. Further analyses showed evidence for purifying selection acting on non-synonymous mutations, even at low frequency of the rare allele, especially in cytochrome oxidase subunit 1 and cytochrome b. The mtDNA of some individuals of Cepaea nemoralis contained a length heteroplasmy, including up to 12 direct repeat copies of tRNA-Val, with 24 copies in another snail, Candidula rugosiuscula, and repeats of tRNA-Thr in C. hortensis. These repeats likely arise due to error prone replication but are not correlated with mitochondrial copy number in C. nemoralis. Overall, the findings provide key insights into mechanisms of replication, mutation and evolution in molluscan mtDNA, and so will inform wider studies on the biology and evolution of mtDNA across animal phyla.
Topics: Animals; Snails; DNA, Mitochondrial; Heteroplasmy; Genome, Mitochondrial; Mutation; DNA Copy Number Variations; Selection, Genetic; Polymorphism, Single Nucleotide
PubMed: 38872121
DOI: 10.1186/s12864-024-10505-w -
Scientific Reports Jun 2024The detection of copy number variations (CNVs) and somatic mutations in cancer is important for the selection of specific drugs for patients with cancer. In cancers with...
The detection of copy number variations (CNVs) and somatic mutations in cancer is important for the selection of specific drugs for patients with cancer. In cancers with sporadic tumor cells, low tumor content prevents the accurate detection of somatic alterations using targeted sequencing. To efficiently identify CNVs, we performed tumor cell enrichment using tissue suspensions of formalin-fixed paraffin-embedded (FFPE) tissue sections with low tumor cell content. Tumor-enriched and residual fractions were separated from FFPE tissue suspensions of intestinal and diffuse-type gastric cancers containing sporadic tumor cells, and targeted sequencing was performed on 225 cancer-related genes. Sequencing of a targeted panel of cancer-related genes using tumor-enriched fractions increased the number of detectable CNVs and the copy number of amplified genes. Furthermore, CNV analysis using the normal cell-enriched residual fraction as a reference for CNV scoring allowed targeted sequencing to detect CNV characteristics of diffuse-type gastric cancer with low tumor content. Our approach improves the CNV detection rate in targeted sequencing with tumor enrichment and the accuracy of CNV detection in archival samples without paired blood.
Topics: Humans; Stomach Neoplasms; DNA Copy Number Variations; Paraffin Embedding; Male; Female; High-Throughput Nucleotide Sequencing; Aged; Mutation
PubMed: 38871991
DOI: 10.1038/s41598-024-64541-3 -
Croatian Medical Journal Jun 2024To determine the spectrum and frequency of disease-causing variants in patients with non-syndromic hearing loss (NSHL) and to investigate the diagnostic yield of the...
AIM
To determine the spectrum and frequency of disease-causing variants in patients with non-syndromic hearing loss (NSHL) and to investigate the diagnostic yield of the applied genetic methods.
METHODS
The study enrolled 306 unrelated patients with childhood-onset, mild-to-profound NSHL referred to Children's Hospital Zagreb for genetic testing between March 2006 and October 2023. The GJB2 variants were analyzed with the multiplex ligation-dependent probe amplification method and Sanger sequencing of the coding region of the GJB2 gene. In 21 patients negative for GJB2 biallelic variants, clinical exome sequencing (CES) was performed.
RESULTS
Among 234 disease-associated GJB2 alleles detected, 19 were clinically relevant, of which 18 were reported as pathogenic/likely pathogenic. The c.35delG variant accounted for 73.5% of the mutated alleles. More than half of the patients with biallelic GJB2 variants (64/110, 58.2%) were 35delG homozygotes. Seventeen non-GJB2 variants were found in 10 genes (TECTA, NOG, SLC26A4, PCDH15, TMPRSS3, USH2A, GATA3, MYO15A, SOX10, COL2A1) in 11 participants, and 5 variants (in TECTA, NOG, PCDH15, and SOX10) were novel (29.4%).
CONCLUSION
We were able to elucidate the genetic cause of hearing loss in 121 patients, with an overall diagnostic rate of 39.5%. The c.35delG was the most common variant. CES allowed us to diagnose almost half of the patients with HL; to distinguish NSHL from the syndromic form of HL in cases where the phenotype was unclear or where symptoms were absent from an early age; and to discover novel variants.
Topics: Humans; Croatia; Child; Connexin 26; Female; Male; Child, Preschool; Adolescent; Infant; Genetic Testing; Genetic Variation; Connexins; Mutation; Exome Sequencing; Hearing Loss; Alleles; Young Adult; Deafness
PubMed: 38868966
DOI: 10.3325/cmj.2024.65.198 -
Heliyon Jun 2024To detect levofloxacin (LFX) and moxifloxacin (MFX) resistance among rifampicin-resistant tuberculosis (RR-TB) isolates, and predict the resistance level based on...
OBJECTIVE
To detect levofloxacin (LFX) and moxifloxacin (MFX) resistance among rifampicin-resistant tuberculosis (RR-TB) isolates, and predict the resistance level based on specific mutations in and genes.
METHODS
A total of 686 RR-TB isolates were collected from Chinese Drug Resistance Surveillance Program from 2013 to 2020. The minimum inhibitory concentrations (MICs) of 12 anti-TB drugs were acquired using the broth microdilution method, followed by whole genome sequencing (WGS) analysis.
RESULTS
Among the 686 RR isolates, the most prevalent resistance was to isoniazid (80.5 %) and ethambutol (28.4 %), followed by LFX (26.1 %) and MFX (21.9 %). The resistance rate of LFX (26.1%-99.4 %) was higher than that of MFX (21.9%-83.3 %) across various drug resistance patterns. Of the 180 fluoroquinolones (FQs) resistant isolates, 168 (93.3 %) had mutations in quinolone-resistant determining regions (QRDRs) with 21 mutation types, and Asp94Gly (32.7 %, 55/168) was the predominant mutation. Isolates with mutations in Asp94Asn and Asp94Gly were associated with high levels of resistance to LFX and MFX. Using broth microdilution method as gold standard, the sensitivities of WGS for LFX and MFX were 93.3 % and 98.0 %, and the specificities were 98.6 % and 95.0 %, respectively.
CONCLUSION
The resistance rate of LFX was higher than that of MFX among various drug resistance patterns in RR-TB isolates. The Asp94Gly was the predominant mutation type underlying FQs resistance. However, no significant difference was observed between mutation patterns in gene and resistance level of FQs.
PubMed: 38868072
DOI: 10.1016/j.heliyon.2024.e31959 -
Cell Communication and Signaling : CCS Jun 2024KRAS-mutant non-small cell lung cancer (NSCLC) shows a relatively low response rate to chemotherapy, immunotherapy and KRAS-G12C selective inhibitors, leading to short...
BACKGROUND
KRAS-mutant non-small cell lung cancer (NSCLC) shows a relatively low response rate to chemotherapy, immunotherapy and KRAS-G12C selective inhibitors, leading to short median progression-free survival, and overall survival. The MET receptor tyrosine kinase (c-MET), the cognate receptor of hepatocyte growth factor (HGF), was reported to be overexpressed in KRAS-mutant lung cancer cells leading to tumor-growth in anchorage-independent conditions.
METHODS
Cell viability assay and synergy analysis were carried out in native, sotorasib and trametinib-resistant KRAS-mutant NSCLC cell lines. Colony formation assays and Western blot analysis were also performed. RNA isolation from tumors of KRAS-mutant NSCLC patients was performed and KRAS and MET mRNA expression was determined by real-time RT-qPCR. In vivo studies were conducted in NSCLC (NCI-H358) cell-derived tumor xenograft model.
RESULTS
Our research has shown promising activity of omeprazole, a V-ATPase-driven proton pump inhibitor with potential anti-cancer properties, in combination with the MET inhibitor tepotinib in KRAS-mutant G12C and non-G12C NSCLC cell lines, as well as in G12C inhibitor (AMG510, sotorasib) and MEK inhibitor (trametinib)-resistant cell lines. Moreover, in a xenograft mouse model, combination of omeprazole plus tepotinib caused tumor growth regression. We observed that the combination of these two drugs downregulates phosphorylation of the glycolytic enzyme enolase 1 (ENO1) and the low-density lipoprotein receptor-related protein (LRP) 5/6 in the H358 KRAS G12C cell line, but not in the H358 sotorasib resistant, indicating that the effect of the combination could be independent of ENO1. In addition, we examined the probability of recurrence-free survival and overall survival in 40 early lung adenocarcinoma patients with KRAS G12C mutation stratified by KRAS and MET mRNA levels. Significant differences were observed in recurrence-free survival according to high levels of KRAS mRNA expression. Hazard ratio (HR) of recurrence-free survival was 7.291 (p = 0.014) for high levels of KRAS mRNA expression and 3.742 (p = 0.052) for high MET mRNA expression.
CONCLUSIONS
We posit that the combination of the V-ATPase inhibitor omeprazole plus tepotinib warrants further assessment in KRAS-mutant G12C and non G12C cell lines, including those resistant to the covalent KRAS G12C inhibitors.
Topics: Carcinoma, Non-Small-Cell Lung; Humans; Lung Neoplasms; Proto-Oncogene Proteins p21(ras); Cell Line, Tumor; Animals; Proto-Oncogene Proteins c-met; Mutation; Omeprazole; Mice; Pyridines; Pyrimidines; Xenograft Model Antitumor Assays; Mice, Nude; Pyrimidinones; Female; Triazines; Antineoplastic Combined Chemotherapy Protocols; Drug Resistance, Neoplasm; Piperazines; Piperidines; Pyridazines; Pyridones
PubMed: 38867255
DOI: 10.1186/s12964-024-01667-x -
Protein Science : a Publication of the... Jul 2024Proteins are constantly undergoing folding and unfolding transitions, with rates that determine their homeostasis in vivo and modulate their biological function. The...
Proteins are constantly undergoing folding and unfolding transitions, with rates that determine their homeostasis in vivo and modulate their biological function. The ability to optimize these rates without affecting overall native stability is hence highly desirable for protein engineering and design. The great challenge is, however, that mutations generally affect folding and unfolding rates with inversely complementary fractions of the net free energy change they inflict on the native state. Here we address this challenge by targeting the folding transition state (FTS) of chymotrypsin inhibitor 2 (CI2), a very slow and stable two-state folding protein with an FTS known to be refractory to change by mutation. We first discovered that the CI2's FTS is energetically taxed by the desolvation of several, highly conserved, charges that form a buried salt bridge network in the native structure. Based on these findings, we designed a CI2 variant that bears just four mutations and aims to selectively stabilize the FTS. This variant has >250-fold faster rates in both directions and hence identical native stability, demonstrating the success of our FTS-centric design strategy. With an optimized FTS, CI2 also becomes 250-fold more sensitive to proteolytic degradation by its natural substrate chymotrypsin, and completely loses its activity as inhibitor. These results indicate that CI2 has been selected through evolution to have a very unstable FTS in order to attain the kinetic stability needed to effectively function as protease inhibitor. Moreover, the CI2 case showcases that protein (un)folding rates can critically pivot around a few key residues-interactions, which can strongly modify the general effects of known structural factors such as domain size and fold topology. From a practical standpoint, our results suggest that future efforts should perhaps focus on identifying such critical residues-interactions in proteins as best strategy to significantly improve our ability to predict and engineer protein (un)folding rates.
Topics: Protein Folding; Protein Stability; Mutation; Plant Proteins; Models, Molecular; Kinetics; Protein Conformation; Peptides
PubMed: 38864692
DOI: 10.1002/pro.5031 -
Proceedings. Biological Sciences Jun 2024An often-overlooked aspect of life-history optimization is the allocation of resources to protect the germline and secure safe transmission of genetic information. While...
An often-overlooked aspect of life-history optimization is the allocation of resources to protect the germline and secure safe transmission of genetic information. While failure to do so renders significant fitness consequences in future generations, germline maintenance comes with substantial costs. Thus, germline allocation should trade off with other life-history decisions and be optimized in accordance with an organism's reproductive schedule. Here, we tested this hypothesis by studying germline maintenance in lines of seed beetle, selected for early (E) or late (L) reproduction for 350 and 240 generations, respectively. Female animals provide maintenance and screening of male gametes in their reproductive tract and oocytes. Here, we reveal the ability of young and aged E- and L-females to provide this form of germline maintenance by mating them to males with ejaculates with artificially elevated levels of protein and DNA damage. We find that germline maintenance in E-females peaks at young age and then declines, while the opposite is true for L-females, in accordance with the age of reproduction in the respective regime. These findings identify the central role of allocation to secure germline integrity in life-history evolution and highlight how females can play a crucial role in mitigating the effects of male germline decisions on mutation rate and offspring quality.
Topics: Animals; Female; Longevity; Germ Cells; Male; Biological Evolution; Reproduction; Coleoptera
PubMed: 38864321
DOI: 10.1098/rspb.2024.0532