Evolutionarily Conserved Research Articles

Orchestrating ROS regulation: coordinated post-translational modification switches in NADPH oxidases.

Reactive oxygen species (ROS) are among the most important signaling molecules, playing a significant role in plant growth, development, and responses to various environmental stresses. Respiratory burst oxidase homologs (RBOHs) are key enzymes in ROS production. Plants tightly regulate the activation and deactivation of RBOHs through various post-translational modifications (PTMs), including phosphorylation, ubiquitination, S-nitrosylation, and persulfidation. These PTMs fine-tune ROS production, ensuring normal plant growth and development while facilitating rapid responses to abiotic and biotic stresses. This review discusses the effects of different PTMs on RBOH function and their biological relevance. Additionally, we examine the evolutionary conservation of PTM sites and emphasize the complex interplay between multiple PTMs regulating RBOHs.

Genetic analysis of preaxial polydactyly: identification of novel variants and the role of ZRS duplications in a Chinese cohort of 102 cases.

Preaxial polydactyly (PPD) is a congenital limb malformation, previously reported to be caused primarily by variants in the ZRS and upstream preZRS regions. This study investigated genetic variations associated with PPD, focusing on point variants and copy number variations (CNVs) in the ZRS and preZRS regions. Comprehensive genetic analyses were conducted on 102 patients with PPD, including detailed clinical examinations and Sanger sequencing of the ZRS and preZRS regions. Additionally, real-time quantitative PCR (qPCR) was used to detect CNVs in the ZRS region. The evolutionary conservation and population frequencies of identified variants were also evaluated. Six point variants were identified, among which four are likely pathogenic novel variants: 93G > T (g.156584477G > T), 106G > A (g.156584464G > A), 278G > A (g.156584292G > A), and 409A > C (g.156585378A > C). Additionally, qPCR analysis revealed that 66.67% of patients exhibited ZRS duplications. Notably, these duplications were also present in cases with newly identified potential pathogenic point variants. These findings suggest the possible interaction of point variants in ZRS and preZRS through a common pathogenic mechanism, leading jointly to PPD. The findings expand the variant spectrum associated with non-syndromic polydactyly and highlight that, despite different classifications, anterior polydactyly caused by variants in ZRS and nearby regions may share common pathogenic mechanisms. The incorporation of various variant types in genetic screening can effectively enhance the rate of pathogenic variant detection and contribute to the cost-effectiveness of genetic testing for limb developmental defects, thereby promoting healthy births.

Unravelling the architecture of major histocompatibility complex class II haplotypes in rhesus macaques.

The regions in the genome that encode components of the immune system are often featured by polymorphism, copy number variation, and segmental duplications. There is a need to thoroughly characterize these complex regions to gain insight into the impact of genomic diversity on health and disease. Here we resolve the organization of complete major histocompatibility complex (MHC) class II regions in rhesus macaques by using a long-read sequencing strategy (Oxford Nanopore Technologies) in concert with adaptive sampling. In particular, the expansion and contraction of the primate DRB-region appear to be a dynamic process that involves the rearrangement of different cassettes of paralogous genes. These chromosomal recombination events are propagated by a conserved pseudogene, DRB6, which features the integration of two retroviral elements. In contrast, the DRA locus appears to be protected from rearrangements, which may be owing to the presence of an adjacently located truncated gene segment, DRB9 With our sequencing strategy, the annotation, evolutionary conservation, and potential function of pseudogenes can be reassessed, an aspect that was neglected by most genome studies in primates. Furthermore, our approach facilitates the characterization and refinement of an animal model essential to study human biology and disease.

Diversity of transactivation regions of DMRT1 in vertebrates

BackgroundDoublesex and mab-3 related transcription factor (DMRT) 1, commonly found in all vertebrates, regulates the transcription of genes involved in the masculinization and maintenance of gonadal somatic cells and/or germline cell development. DMRT1 has a DNA-binding domain called the DM domain and a transcription regulatory region. Unlike the former, there is little knowledge about the latter transcription regulatory region. This study aimed to identify the transcription activation regions of DMRT1 from four species: humans and mice (mammals), leopard geckos (reptiles), and medaka (teleost fish), adding perspectives on evolutionary conservation and diversity.Methods and resultsFor each species, several expression plasmids of deletion mutants were constructed, and the resultant plasmid and a DMRT1-driven luciferase reporter were co-transfected into cultured cells to measure transactivation ability. The key point of this analysis is that the transactivation ability was normalized by quantifying the expression levels of DMRT1 variants using the HiBiT tag. As a result, two to three transactivation regions were suggested to exist in the C-terminal region of the DM domain in all four species. Among seven regions in DMRT1, the fourth region from the N-terminus contributed to transactivation common to the four species, and the sixth and seventh regions on the C-terminal side differed depending on the species.ConclusionsThese findings indicated that the regions involved in the transactivation ability of DMRT1 could subtly change during evolution, indicating diversity in transactivation domains.

Behavioral screening reveals a conserved residue in Y-Box RNA-binding protein required for associative learning and memory in C. elegans.

RNA-binding proteins (RBPs) regulate translation and plasticity which are required for memory. RBP dysfunction has been linked to a range of neurological disorders where cognitive impairments are a key symptom. However, of the 2,000 RBPs in the human genome, many are uncharacterized with regards to neurological phenotypes. To address this, we used the model organism C. elegans to assess the role of 20 conserved RBPs in memory. We identified eight previously uncharacterized memory regulators, three of which are in the C. elegans Y-Box (CEY) RBP family. Of these, we determined that cey-1 is the closest ortholog to the mammalian Y-Box (YBX) RBPs. We found that CEY-1 is both necessary in the nervous system for memory ability and sufficient to promote memory. Leveraging human datasets, we found both copy number variation losses and single nucleotide variants in YBX1 and YBX3 in individuals with neurological symptoms. We identified one predicted deleterious YBX3 variant of unknown significance, p.Asn127Tyr, in two individuals with neurological symptoms. Introducing this variant into endogenous cey-1 locus caused memory deficits in the worm. We further generated two humanized worm lines expressing human YBX3 or YBX1 at the cey-1 locus to test evolutionary conservation of YBXs in memory and the potential functional significance of the p.Asn127Tyr variant. Both YBX1/3 can functionally replace cey-1, and introduction of p.Asn127Tyr into the humanized YBX3 locus caused memory deficits. Our study highlights the worm as a model to reveal memory regulators and identifies YBX dysfunction as a potential new source of rare neurological disease.

The Neural Correlations of Olfactory Associative Reward Memories in Drosophila.

Advancing treatment to resolve human cognitive disorders requires a comprehensive understanding of the molecular signaling pathways underlying learning and memory. While most organ systems evolved to maintain homeostasis, the brain developed the capacity to perceive and adapt to environmental stimuli through the continuous modification of interactions within a gene network functioning within a broader neural network. This distinctive characteristic enables significant neural plasticity, but complicates experimental investigations. A thorough examination of the mechanisms underlying behavioral plasticity must integrate multiple levels of biological organization, encompassing genetic pathways within individual neurons, interactions among neural networks providing feedback on gene expression, and observable phenotypic behaviors. Model organisms, such as Drosophila melanogaster, which possess more simple and manipulable nervous systems and genomes than mammals, facilitate such investigations. The evolutionary conservation of behavioral phenotypes and the associated genetics and neural systems indicates that insights gained from flies are pertinent to understanding human cognition. Rather than providing a comprehensive review of the entire field of Drosophila memory research, we focus on olfactory associative reward memories and their related neural circuitry in fly brains, with the objective of elucidating the underlying neural mechanisms, thereby advancing our understanding of brain mechanisms linked to cognitive systems.

Molecular dynamics simulations involving different β-propeller mutations reported in Swiss and French patients correlate with their disease phenotypes

Integrin αIIbβ3 is the predominant receptor for fibrinogen which mediates platelet aggregation, an important step in hemostasis and thrombosis. Several mutations have been reported in the genes encoding αIIb and β3 subunits among patients with Glanzmann thrombasthenia, of which 177 are in the β-propeller domain. The two subunits form a heterodimer at the interface between β-propeller and β-I domains of αIIb and β3, respectively with their stability critical for intracellular trafficking, surface expression, and ligand binding. Our study was aimed at retrieving the β-propeller mutations from various databases and studying structural variations due to select mutations upon interaction with fibrinogen using molecular docking and molecular dynamics. Mutations were studied for their impact on phenotypic severity, structural stability, and evolutionary conservation. Molecular docking analysis and molecular dynamics simulations were carried out for αIIb-β3 complexes as well as αIIbβ3-fibrinogen complexes; in particular, E355K structure had more deviations, fluctuations, and other changes which compromised its structural stability and binding affinity when compared to both wild-type and G401C structures. Our comprehensive in silico analysis clearly reiterates that mutations in the β-propeller are not only responsible for structural changes in this domain but also have implications on the overall structure and function of integrin αIIbβ3.

Long range segmentation of prokaryotic genomes by gene age and functionality.

Bacterial and archaeal genomes encompass numerous operons that typically consist of two to five genes. On larger scales, however, gene order is poorly conserved through the evolution of prokaryotes. Nevertheless, non-random localization of different classes of genes on prokaryotic chromosomes could reflect important functional and evolutionary constraints. We explored the patterns of genomic localization of evolutionarily conserved (ancient) and variable (young) genes across the diversity of bacteria and archaea. Nearly all bacterial and archaeal chromosomes were found to encompass large segments of 100-300 kb that were significantly enriched in either ancient or young genes. Similar clustering of genes with lethal knockout phenotype (essential genes) was observed as well. Mathematical modeling of genome evolution suggests that this long-range gene clustering in prokaryotic chromosomes reflects perpetual genome rearrangement driven by a combination of selective and neutral processes rather than evolutionary conservation.

Characterization of the complete mitochondrial genome of the Sunda stink-badger (Mydaus javanensis) from the island of Borneo.

The Mephitidae is a family of skunks and stink-badgers that includes 12 extant species in four genera, namely, Mydaus, Conepatus, Mephitis and Spilogale. Mydaus is the only genus within Mephitidae found outside the American continent, with its distribution limited to the islands of Borneo, Indonesia and Philippines. There are two extant species of Mydaus i.e., javanensis and marchei. Currently, complete mitogenomes are unavailable for either species. Here, we present the characterization of the first complete mitogenome for the Sunda stink-badger (Mydaus javanensis) from the island of Borneo. Muscle tissue was obtained and the DNA was sequenced using a combination of Illumina Barcode Tagged Sequence (BTSeq) and Sanger sequencing techniques. The genome was annotated with MITOS and manually checked for accuracy. A circular map of the mitogenome was constructed with Proksee. Relative synonymous codon usage (RSCU) and codon frequency were calculated using MEGA-X. The protein coding genes (PCGs) were aligned with reference sequences from GenBank and used for the construction of phylogenetic trees (maximum liklihood (ML) and Bayesian inference (BI)). Additionally, due to the lack of available complete genomes in public databases, we constructed another tree with the cyt b gene. The complete circular mitogenome was 16,391 base pairs in length. It comprises the typical 13 protein-coding genes, 22 tRNAs, two ribosomal RNA genes, one control region (CR) and an L-strand replication origin (OL). The G+C content was 38.1% with a clear bias towards A and T nucleotides. Of the 13 PGCs, only ND6 was positioned in the reverse direction, along with five other tRNAs. Five PCGs had incomplete stop codons and rely on post-transcriptional polyadenylation (TAA) for termination. Based on the codon count, Leucine was the most common amino acid (589), followed by Threonine (332) and Isoleucine (325). The ML and BI phylogenetic trees, based on concatenated PCGs and the cyt b gene, respectively, correctly clustered the species with other members of the Mephitidae family but were unique enough to set it apart from Conepatus, Mephitis and Spilogale. The results confirm Mydaus as a member of the mephitids and the mitogenome will be useful for evolutionary analysis and conservation of the species.

ProEnd: a comprehensive database for identifying HbYX motif-containing proteins across the tree of life

The proteasome plays a crucial role in cellular homeostasis by degrading misfolded, damaged, or unnecessary proteins. Understanding the regulatory mechanisms of proteasome activity is vital, particularly the interaction with activators containing the hydrophobic-tyrosine-any amino acid (HbYX) motif. Here, we present ProEnd, a comprehensive database designed to identify and catalog HbYX motif-containing proteins across the tree of life. Using a simple bioinformatics pipeline, we analyzed approximately 73 million proteins from 22,000 reference proteomes in the UniProt/SwissProt database. Our findings reveal the widespread presence of HbYX motifs in diverse organisms, highlighting their evolutionary conservation and functional significance. Notably, we observed an interesting prevalence of these motifs in viral proteomes, suggesting strategic interactions with the host proteasome. As validation two novel HbYX proteins found in this database were experimentally tested by pulldowns, confirming that they directly interact with the proteasome, with one of them directly activating it. ProEnd’s extensive dataset and user-friendly interface enable researchers to explore the potential proteasomal regulator landscape, generating new hypotheses to advance proteasome biology. This resource is set to facilitate the discovery of novel therapeutic targets, enhancing our approach to treating diseases such as neurodegenerative disorders and cancer.

Seeing the unseen in characterizing RNA editome during rice endosperm development

Rice (Oryza sativa L.) endosperm is essential to provide nutrients for seed germination and determine grain yield. RNA editing, a post-transcriptional modification essential for plant development, unfortunately, is not fully characterized during rice endosperm development. Here, we perform systematic analyses to characterize RNA editome during rice endosperm development. We find that most editing sites are C-to-U CDS-recoding in mitochondria, leading to increased hydrophobic amino acids and changed structures of mitochondrial proteins. Comparative analysis of RNA editome reveals that CDS-recoding sites present higher editing frequencies with lower variabilities and their resultant recoded amino acids tend to exhibit stronger evolutionary conservation across many land plants. Furthermore, we classify mitochondrial genes into three groups, presenting distinct patterns in terms of CDS-recoding events. Besides, we conduct genome-wide screening to detect pentatricopeptide repeat (PPR) proteins and construct PPR-RNA binding profiles, yielding candidate PPR editing factors related to rice endosperm development. Taken together, our findings provide valuable insights for deciphering fundamental mechanisms of rice endosperm development underlying RNA editing machinery.

X-ray crystal structure of proliferating cell nuclear antigen 1 from Aeropyrum pernix.

Proliferating cell nuclear antigen (PCNA) plays a critical role in DNA replication by enhancing the activity of various proteins involved in replication. Inthis study, the crystal structure of ApePCNA1, one of three PCNAs from thethermophilic archaeon Aeropyrum pernix, was elucidated. ApePCNA1 was cloned and expressed in Escherichia coli and the protein was purified and crystallized. The resulting crystal structure determined at 2.00 Å resolution revealed that ApePCNA1 does not form a trimeric ring, unlike PCNAs from other domains of life. It has unique structural features, including a long interdomain-connecting loop and a PIP-box-like sequence at the N-terminus, indicating potential interactions with other proteins. These findings provide insights into the functional mechanisms of PCNAs in archaea and their evolutionary conservation across different domains of life. A modified medium and protocol were used to express recombinant protein containing the lac operon. The expression of the target protein increased and the total incubation time decreased when using this system compared with those of previous expression protocols.

Computational Analyses of Amino Acid Molecules in PDE7A for Elucidating their Evolutionary Diversity and Protein Interactions in Multiple Mammalian Species

This study explores the protein interactions and evolutionary conservation of phosphodiesterase type 7A (PDE7A) across different species, to identify the species with the highest similarity to humans, which has important applications in many fields such as pharmacology, comparative biology, biochemistry, oncology, endocrinology, and reproductive sciences. Computational analyses of the amino acid sequence of this enzyme revealed a common evolutionary relationship between the selected species and humans, but camels show the most variable evolutionary lineage in their PDE7A protein over time. In searches for homologous proteins, identity analysis results for four returned amino acid sequences were as follows: 91.81 ± 4.25% (mean ± SD), while the similarity between the sequences was 94.66% ± 4.55, and analysis of BLOSUM62 (Blocks Substitution Matrix 62) yielded a minimum value of 0.901 ± 0.055. All species have closely related physicochemical properties. The computational analyses revealed conserved amino acid residues of the gene across the studied species, which likely contribute to the similar expression patterns of the PDE7A gene in various animals. The findings also suggest that rats are a suitable model for gaining deeper insights into human biology.

Palaeognaths Reveal Evolutionary Ancestry of the Avian Major Histocompatibility Complex Class II.

The multigene family of the major histocompatibility complex (MHC) codes for the key antigen-presenting molecules of the vertebrate immune system. In birds, duplicated MHC class II (MHC-II) genes are highly homogenized by concerted evolution, and thus, identification of their orthologous relationships across long evolutionary timescales remains challenging. Relatively low evolutionary rate of avian MHC class IIA genes has been expected to provide a promising avenue to allow such inferences, but availability of MHC-IIA sequences in nonmodel bird species has been limited until recently. Here, taking advantage from accumulating genomic resources, we identified and analyzed MHC-IIA sequences from the most basal lineage of extant birds (Palaeognathae). Conserved region of the MHC-IIA membrane-proximal domain was used to search for orthologous relationships between palaeognath birds and nonavian reptiles. First, analyses of palaeognath sequences revealed the presence of a separate MHC-IIA gene lineage (DAA3) in kiwis, which did not cluster with previously described avian MHC-IIA lineages (DAA1 and DAA2). Next, phylogenetic reconstruction showed that kiwi DAA3 sequences form a single well-supported cluster with turtle MHC-IIA. High similarity of these sequences most likely reflects their remarkable evolutionary conservation and retention of ancient orthologous relationships, which can be traced back to basal archosauromorphs ca. 250 million years ago. Our analyses offer novel insights into macroevolutionary history of the MHC and reinforce the view that rapid accumulation of high-quality genome assemblies across divergent nonmodel species can substantially advance our understanding of gene evolution.

The complete mitochondrial genome and phylogenetic analysis for Rhabdophis chiwen (squamata: colubridae)

Rhabdophis chiwen is currently found so far in Sichuan Province, China, where it predominantly feeds on earthworms and firefly larvae. In this study, we sequenced and analyzed the mitochondrial genome of R. chiwen, which measured 17,646 bp in length and encompassed 37 genes along with two control regions. The base composition revealed percentages of 33.20% A, 25.94% T, 13.27% G, and 27.59% C. Phylogenetic analyses indicate that R. chiwen belongs to the family Colubridae and forms a sister branch with R. tigrinus. This study successfully obtained the first complete mitochondrial genome of R. chiwen, offering crucial genetic data for its evolutionary history and conservation.

Exploring Influential Factors on Biomass and Diversity of Ancient Trees in Human-Dominated Regions: A Case Study in Guangdong Province, China

Ancient trees, which are vital for biodiversity and cultural heritage, maintain species richness, ecosystem resilience, and societal interconnectedness. However, escalating global climate change and human activities have led to widespread declines in ancient tree diversity and habitat degradation. Hence, understanding ancient tree dynamics is vital for precise conservation strategies, fostering harmony between society and ecology. This study addresses the gap in understanding the factors influencing ancient tree biomass and diversity in human-dominated areas. This study first collected biomass equations for ancient tree species. The biomass of ancient trees within human-influenced regions of Guangdong Province was subsequently computed in detail. Finally, by employing a structural equation model, we sought to quantitatively elucidate the influence of natural variables (encompassing geography, topography, soil composition, and climatic conditions) alongside anthropogenic variables (including population density, per capita GDP, the human footprint, ancient villages, and religious sites) on both the biomass and species richness of ancient trees. The species with the highest total biomass included Ficus microcarpa L.f. (2.45×105 t), Ficus concinna (Miq.) Miq. (4.07×104 t), and Litchi chinensis Sonn. (3.16×104 t). Moreover, the biomass presented a pronounced phylogenetic signal and evolutionary conservation. According to the results of the structural equation model, across the entire study area, soil characteristics emerged as the most influential predictor among the natural factors ( β = -0.14), whereas population density stood out as the foremost predictor among the anthropogenic factors (β = 0.23). Notably, both climatic conditions and anthropogenic factors contributed positively to an increase in ancient tree biomass (β = 0.02) (β = 0.07), albeit concurrently leading to a decrease in species richness (β = -0.05) (β = -0.08). In regions characterized by high levels of disturbance, anthropogenic factors indirectly increase biomass by increasing the abundance of large-diameter ancient trees (β = 0.28) while concurrently decreasing species richness (β = -0.11). Conversely, in areas with low levels of disturbance, anthropogenic influences also indirectly increase biomass (β = 0.19) by fostering the growth of large-diameter ancient trees while simultaneously promoting species richness (β = 0.01). This study investigated biomass and diversity factors in ancient trees within human-dominated regions of Guangdong Province. This study provides insights into ecosystem determinants, informing conservation strategies and contributing to biodiversity preservation amid societal and environmental dynamics.

Adaptive evolution and functional significance of the PPARGC1A gene across diverse animal species.

Codon-based analyses of the PPARGC1A gene across 38 vertebrate species were deployed to elucidate patterns of evolutionary change. Employing maximum likelihood assessments through MEGA, we scrutinized 447 codon positions addressing the entire coding region, excluding positions mired by gaps or missing data. Distinct codons manifested variance in selection pressures, particularly codons 4, 11, 66, and 123, which exhibited positive dN-dS values suggestive of positive selection. Codon 137 displayed the most pronounced dN-dS value, signifying intensified selective advantage. Meanwhile, codons 30 and 90 portrayed near-neutral scores, indicative of purifying selection. Complementary computational methods (IFEL, REL, FUBAR, and SLAC) confirmed positive selection at specific codon sites, with varying degrees of corroboration. The integration of mixed-effect modeling (MEME) identified episodic diversifying selection, pinpointing codons that underwent selection episodes in certain lineages. Refined codon model selection lent insight into substitution rates, revealing nuanced degrees of evolutionary conservation among different codons. Supporting these genetic insights, the phylogenetic analysis highlighted relationships among the PPARGC1A sequences and domain analysis confirmed conserved features across species, while protein-protein interaction networks suggested a complex web of functional interdependencies. These findings advance our understanding of the PPARGC1A gene's evolutionary trajectory and underscore the gene's potential adaptive significance within diverse vertebrate lineages.

Glutamine Synthetase and Glutamate Synthase Family Perform Diverse Physiological Functions in Exogenous Hormones and Abiotic Stress Responses in Pyrus betulifolia Bunge (P.be)

The unscientific application of nitrogen (N) fertilizer not only increases the economic input of pear growers but also leads to environmental pollution. Improving plant N use efficiency (NUE) is the most effective economical method to solve the above problems. The absorption and utilization of N by plants is a complicated process. Glutamine synthetase (GS) and glutamate synthase (GOGAT) are crucial for synthesizing glutamate from ammonium in plants. However, their gene family in pears has not been documented. This study identified 29 genes belonging to the GS and GOGAT family in the genomes of Pyrus betulaefolia (P.be, 10 genes), Pyrus pyrifolia (P.py, 9 genes), and Pyrus bretschneideri (P.br, 10 genes). These genes were classified into two GS subgroups (GS1 and GS2) and two GOGAT subgroups (Fd–GOGAT and NADH–GOGAT). The similar exon–intron structures and conserved motifs within each cluster suggest the evolutionary conservation of these genes. Meanwhile, segmental duplication has driven the expansion and evolution of the GS and GOGAT gene families in pear. The tissue–specific expression dynamics of PbeGS and PbeGOGAT genes suggest significant roles in pear growth and development. Cis–acting elements of the GS and GOGAT gene promoters are crucial for plant development, hormonal responses, and stress reactions. Furthermore, qRT–PCR analysis indicated that PbeGSs and PbeGOGATs showed differential expression under exogenous hormones (GA3, IAA, SA, ABA) and abiotic stress (NO3− and salt stress). In which, the expression of PbeGS2.2 was up–regulated under hormone treatment and down–regulated under salt stress. Furthermore, physiological experiments demonstrated that GA3 and IAA promoted GS, Fd–GOGAT, and NADH–GOGAT enzyme activities, as well as the N content. Correlation analysis revealed a significant positive relationship between PbeGS1.1, PbeGS2.2, PbeNADH–GOGATs, and the N content. Therefore, PbeGS1.1, PbeGS2.2, and PbeNADH–GOGATs could be key candidate genes for improving NUE under plant hormone and abiotic stress response. To the best of our knowledge, our study provides valuable biological information about the GS and GOGAT family in the pear for the first time and establishes a foundation for molecular breeding aimed at developing high NUE pear rootstocks.

Chromosome-specific barcode system with centromeric repeat in cultivated soybean and wild progenitor.

Wild soybean Glycine soja is the progenitor of cultivated soybean Glycine max Information on soybean functional centromeres is limited despite extensive genome analysis. These species are an ideal model for studying centromere dynamics for domestication and breeding. We performed a detailed chromatin immunoprecipitation analysis using centromere-specific histone H3 protein to delineate two distinct centromeric DNA sequences with unusual repeating units with monomer sizes of 90-92 bp (CentGm-1) and 413-bp (CentGm-4) shorter and longer than standard nucleosomes. These two unrelated DNA sequences with no sequence similarity are part of functional centromeres in both species. Our results provide a comparison of centromere properties between a cultivated and a wild species under the effect of the same kinetochore protein. Possible sequence homogenization specific to each chromosome could highlight the mechanism for evolutionary conservation of centromeric properties independent of domestication and breeding. Moreover, a unique barcode system to track each chromosome is developed using CentGm-4 units. Our results with a unifying centromere composition model using CentGm-1 and CentGm-4 superfamilies could have far-reaching implications for comparative and evolutionary genome research.

Multi-species genome-wide CRISPR screens identify conserved suppressors of cold-induced cell death.

Cells must adapt to environmental changes to maintain homeostasis. One of the most striking environmental adaptations is entry into hibernation during which core body temperature can decrease from 37°C to as low at 4°C. How mammalian cells, which evolved to optimally function within a narrow range of temperatures, adapt to this profound decrease in temperature remains poorly understood. In this study, we conducted the first genome-scale CRISPR-Cas9 screen in cells derived from Syrian hamster, a facultative hibernator, as well as human cells to investigate the genetic basis of cold tolerance in a hibernator and a non-hibernator in an unbiased manner. Both screens independently revealed glutathione peroxidase 4 (GPX4), a selenium-containing enzyme, and associated proteins as critical for cold tolerance. We utilized genetic and pharmacological approaches to demonstrate that GPX4 is active in the cold and its catalytic activity is required for cold tolerance. Furthermore, we show that the role of GPX4 as a suppressor of cold-induced cell death extends across hibernating species, including 13-lined ground squirrels and greater horseshoe bats, highlighting the evolutionary conservation of this mechanism of cold tolerance. This study identifies GPX4 as a central modulator of mammalian cold tolerance and advances our understanding of the evolved mechanisms by which cells mitigate cold-associated damage-one of the most common challenges faced by cells and organisms in nature.