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Primary mitochondrial diseases are a heterogeneous group of neurometabolic disorders recognized as the most common metabolic genetic diseases. They manifest at any age, affecting any tissue or organ, especially those with high energy demands, and are caused by pathogenic variants in both mitochondrial and nuclear genomes. Here, we aimed to describe the genetic spectrum of a Tunisian pediatric cohort with suspected mitochondrial diseases. We recruited 47 unrelated families who underwent exome sequencing as a first-tier test followed by whole mitochondrial genome sequencing for unsolved cases. Dedicated bioinformatic pipelines and prediction tools were used to determine the potential disease-causing variants. Sanger sequencing confirmed the presence and segregation within parents. For the newly identified variants, structural modeling was conducted to study the impact of these variants on protein structure and motions. Dual genome sequencing yielded a molecular diagnosis in 33/47 families (70%) and 18/47 (38%) showed disease-causing variants in genes encoding mitochondrial proteins. Among them, four families disclosed novel variants in FASTKD2, SERAC1 and GATB, which were supported by in-depth in silico and structural analyses demonstrating their deleterious effect. The remaining families (32%, 15/47) disclosed other metabolic and neurological disorders. An exome-first strategy delivers a high diagnostic yield in Tunisia, where consanguinity remains high and simultaneously captures mitochondrial and non-mitochondrial etiologies. Mitochondrial sequencing remains indispensable in the case of an inconclusive exome. Thus, our data expand the clinical and genetic spectrum of primary mitochondrial diseases in Tunisia, an underrepresented and admixed population.
During the intracellular replication cycle of West Nile virus (WNV), genome RNA synthesis is initially inefficient but increases exponentially as viral replication complexes are sequestered in invaginations in the endoplasmic reticulum. In this study, we investigated the functional role of the cellular protein TIAR (T-cell intracellular antigen-related protein) in the transcription of WNV genome RNA. Close colocalization of cytoplasmic TIAR with viral double-stranded RNA was detected by a proximity ligation assay in WNV-infected cells. TIAR binds specifically to the WNV 3'(-) SL but not to the complementary WNV 5'(+) SL in in vitro RNA binding assays. Only the 3' end of the WNV minus-strand RNA was enriched by immunoprecipitation of infected cell lysates with anti-TIAR antibody. Stable overexpression of TIAR in clonal A549 cells increased the ratio of intracellular viral plus-strand to minus-strand RNA in a dose-dependent manner. TIAR contains three RNA recognition motifs (RRMs). Biophysical data indicated that only RRM2 directly contacts RNA and that up to three TIAR molecules can bind cooperatively to the WNV 3'(-) SL RNA. These data provide additional evidence that TIAR functions as a proviral host factor facilitating exponential amplification of WNV genome production in infected cells.IMPORTANCEWest Nile virus (WNV) is a mosquito-borne orthoflavivirus associated with increasing global human disease incidence. The molecular mechanisms underlying viral replication are not fully understood. In early stages of infection, viral genome transcription is inefficient; however, in late stages, viral genome transcription increases exponentially. T-cell intracellular antigen-related (TIAR) protein is a cellular protein that has been shown to interact with the 3' end of the WNV negative-sense antigenomic RNA. We obtained data showing colocalization of cellular TIAR with viral replication complexes in infected cells and an increased ratio of intracellular genomic to antigenomic viral RNA in TIAR-overexpressing cells, and confirmed preferential binding of TIAR to the 3' end of the WNV antigenome both in vitro and in infected cell extracts. We also demonstrated that multiple TIAR proteins can bind cooperatively to the WNV 3'(-) stem-loop RNA. These data provide supporting evidence for a model of TIAR-mediated rapid initiation of nascent genome RNA synthesis in infected cells.
Six Gloeotrichia echinulata genomes derived from planktonic harmful algal blooms (HABs) with similar colonial morphology have been sequenced from lakes in the west and northeast regions of USA, four of them to completion. The c. 7 Mbp genomes exhibit a high level of conservation, with 98-99% pairwise genome-wide average nucleotide identity and high levels of synteny, representing a single species cluster. We observed strong conservation of gene clusters responsible for the synthesis of the secondary metabolites and bioactive peptides that are characteristic of HAB-forming cyanobacteria. All six G. echinulata genomes lack genes for the synthesis of classic cyanotoxins, including microcystin, but possess genes responsible for the synthesis of the taste and odor compound geosmin. Interestingly, the geoA geosmin synthase gene in three genomes is homologous to other cyanobacterial geoA genes, while the other three geoA genes are related to actinomyces geoA. Phylogenomic analysis places the G. echinulata genomes within a clade of benthic Nostocales, reflecting an ecological niche featuring extensive growth on the sediment surface before colonies disperse into the epilimnion for planktonic growth. We identify genes conserved in all six genomes that could represent physiological adaptations supporting active growth on sediments and pelagic recruitment independent of wind-driven mixing: phycoerythrin light harvesting complexes for optimal photosynthesis at depth; gliding motility to access patchy nutrient distributions; and gas vesicles with relatively small GvpC proteins that predict resistance to higher hydrostatic pressure. The strong genomic similarity across geographically distant populations suggests that G. echinulata in the United States is a tightly related non-toxigenic species group with predictable properties relevant to public health and drinking water management.
LYSINE-SPECIFIC DEMETHYLASE 1-like (LDL) proteins are conserved FAD-dependent amine oxidases that serve as pivotal regulators in plants. While animal systems typically rely on a single LSD1/KDM1A enzyme, the Arabidopsis thaliana genome encodes an expanded family of LDL homologues (FLD, LDL1, LDL2, and LDL3), resulting in substantial subfunctionalization and specialized recruitment mechanisms. This review explores the diverse developmental roles of plant LDLs, ranging from flowering time and circadian clock regulation to heterochromatin maintenance and epigenetic regulation. We discuss the redundant roles of FLD, LDL1, and LDL2 in repressing the floral repressor FLC and their nonredundant specialized function within the CCA1/LHY-TOC1 circadian feedback loop. A central focus of our review is the emerging mechanism of transcription-coupled demethylation, in which LDLs associate with the phosphorylated C-terminal domain of RNA polymerase II to modify chromatin cotranscriptionally within gene bodies. By integrating findings from Arabidopsis thaliana and crops such as tomato and soybean, we illustrate how the diversified LDL-mediated regulatory toolkit facilitates precise, gene-specific regulation. Ultimately, the LDL family represents a cornerstone of the sophisticated epigenetic strategies that regulate plant phenotypic plasticity in response to developmental and environmental cues.
Nonsense-mediated mRNA decay (NMD) is one of the most extensively studied pathways of cytoplasmic mRNA degradation. It plays a critical role in diverse cellular processes by eliminating aberrant transcripts containing premature stop codons and by regulating the stability of physiological mRNAs. NMD factors were initially identified through genetic screens in S. cerevisiae (UPF1, 2, 3) and C. elegans (SMG-1, SMG5-7). Subsequent biochemical and genetic studies revealed the composition of NMD complexes and identified additional factors. A major protein hub for NMD is Upf1, an ATP-dependent RNA helicase that is part of two mutually exclusive NMD assemblies, the Upf1-Upf2-Upf3 complex and the Upf1-decapping complex, which contains the decapping enzyme and its co-factors. Here, we discuss recent findings, primarily from budding yeast, on the protein-protein interactions driving NMD complexes dynamics and their similarities to human NMD. Together, the N-terminal cysteine and histidine rich (CH) and helicase domains (HD) of Upf1 act as a hub for binding multiple partners. Upf1 is required for binding to NMD substrates and for the initiation of RNA degradation through decapping (yeast) or endonucleolytic hydrolysis (humans). We focus on the interplay between Upf2, Dcp2 and Nmd4 (yeast SMG6), which ensures the mutually exclusive formation of Upf1-bound subcomplexes modulating Upf1's affinity for RNA. Thus, the study of NMD factors interactions in different organisms sheds new light on the remarkable conservation of NMD molecular mechanisms.
BACKGROUND: The inflammasome is a critical immunological sensor comprised of NLRP-3, ASC, and CASPASE-1. Mutations in NLRP-3 are prevalent in inflammatory diseases. However, the role of NLRP-3 in cancer is controversial. This study investigates whether NLRP-3 expression is associated with clinical outcomes in patients with solid cancers. METHODS: PubMed (MEDLINE), Embase, Cochrane, and Google Scholar were searched for articles reporting NLRP-3 expression and disease outcome data in cancer patients. RevMan Review Manager was used to calculate pooled hazard ratios and Mantel-Haenszel pooled odds ratios. RNA sequencing datasets from the TCGA Pan-Cancer (PANCAN) were used for external validation. RESULTS: Patients with higher NLRP-3 expression showed a significant association with larger tumor size, advanced tumor grade, TNM stage, and presence of metastasis. High NLRP-3 expression has a significant association with poor OS (HR:2.12, 95% CI = 1.49-3.03), p < 0.0001) and DFS (HR:1.86, 95% CI = 1.30- 2.65, p = 0.0007). Subgroup analysis showed that higher NLRP-3 expression is associated with worse OS in head and neck cancer (HR: 2.77, 95% CI = 1.88-4.09, p < 0.00001), colorectal cancers (HR:2.14, 95% CI= 1.59- 2.87, p < 0.00001), and pancreatic cancer patients (HR: 3.19, 95% CI = 1.73-5.91, p = 0.0002). CONCLUSION: High NLRP-3 expression is associated with advanced disease and poor outcomes in many solid tumours.
Katsuobushi is a traditional processed seafood product used in Japanese-style cooking, and when it is produced through fermentation by fungi, it is called karebushi. The fungi involved in katsuobushi fermentation are collectively referred to as katsuobushi molds. We previously discovered seven novel viruses from katsuobushi molds and determined their genome sequences. However, our previous explorations used only nine fungal strains available from culture collections, leaving the diversity of viruses infecting fungi involved in katsuobushi fermentation unclear. Therefore, in this study, we aimed to isolate fungi from commercially available karebushi and clarify the prevalence of viruses in the isolates. Karebushi produced by three manufacturers was obtained, and 30 fungal strains (including Aspergillus spp.) were isolated from each. Double-stranded RNA (dsRNA) fractions were prepared from the mycelia of the isolated strains. Electrophoresis suggested that a relatively high proportion of the isolates harbored dsRNA elements consistent with RNA virus infection (30-70% per manufacturer; 59% overall). Furthermore, dsRNA sequencing identified four novel viruses in isolates of Aspergillus chevalieri and Aspergillus montevidensis: a beny-like virus, a gammapartitivirus, a narnavirus, and a victorivirus, in addition to two previously reported viruses. Notably, this represents the first report of a beny-like virus in Aspergillus spp. This study provides insights into the diversity of viruses infecting fungi involved in katsuobushi fermentation.
AIMS/HYPOTHESIS: The breastmilk microbiome plays a crucial role in gut microbial colonisation and immune development, but little is known about how it is influenced by type 1 diabetes. METHODS: We conducted a longitudinal 16S rRNA gene sequencing study of milk from women with type 1 diabetes (n=69 pregnancies; 174 samples) and women who did not have type 1 diabetes (n=49 pregnancies; 123 samples), collected at seven timepoints from birth to 15 months postpartum. Alpha diversity (richness, inverse Simpson evenness) was analysed by generalised linear mixed models, beta diversity was analysed by Bray-Curtis dissimilarities and PERMANOVA, and differential abundance was analysed by limma. Additionally, we examined associations with maternal genetic risk score (GRS), maternal HLA type, glycaemic management (HbA1c) and breastmilk secretory IgA (sIgA), and performed a parallel analysis for the infant stool microbiome. RESULTS: A significant interaction between type 1 diabetes status and timepoint was observed for alpha diversity, both richness (p=0.01) and inverse Simpson diversity (p=0.003), indicating distinct temporal trajectories between women with and without type 1 diabetes. In those without type 1 diabetes, richness increased significantly between birth and 1 week postpartum, but this early increase was delayed in women with type 1 diabetes to between 1 week and 3 months postpartum (p=0.002). Beta diversity analysis revealed earlier and more extensive compositional shifts in women without type 1 diabetes compared to those with type 1 diabetes. These differences persisted after adjusting for Caesarean delivery, BMI, parity and infant sex, and were not attributable to a delay in initiating breastfeeding. Taxa with delayed enrichment in women with type 1 diabetes included Streptococcus spp. and Rothia mucilaginosa, which metabolise human milk oligosaccharides to short-chain fatty acids to promote development of the infant's gut barrier and immune system. Maternal GRS, HLA, HbA1c or sIgA were not associated with milk microbiota diversity trajectories. In infant stool samples, alpha diversity did not differ between exposure groups, and showed no evidence of delayed maturation. Beta diversity revealed an early compositional shift between birth and 1 week postpartum only in infants born to women without type 1 diabetes. Similarly, significant taxonomic changes between birth and 1 week postpartum were detected only in infants born to women without type 1 diabetes, but with some taxa differing between exposure groups at 1 week. CONCLUSIONS/INTERPRETATION: Maternal type 1 diabetes is associated with delayed early maturation of the breastmilk microbiome. Early compositional differences in microbiota restructuring were also observed in the infant gut, partially mirroring the pattern in the milk microbiome; however, sustained differences in infant gut microbiota diversity were not detected. Further investigation could determine whether these changes affect development of the infant's gut and immune system.
Obstacles to translation elongation stall ribosomes and allow deleterious proteins to accumulate, which threatens cellular health. Cells recognize and clear stalled ribosomes via several interrelated pathways, although the mechanisms by which cells distinguish stalled from normally elongating ribosomes and mount an appropriate response are incompletely understood. While recent work highlights how ribosome collisions help cells to recognize stalled ribosomes, how other factors contribute to detection remains unclear. Here, we report a requirement for the translational factor eIF5A in the mRNA decay response to ribosomal stalling, i.e., No-Go mRNA Decay (NGD). We identified the Caenorhabditis elegans polyamine transporter, catp-6, via a forward genetic screen as a factor required for NGD. During our mechanistic dissection of the catp-6 phenotype, we uncovered a role for cellular polyamines and the translation elongation factor eIF5A in NGD, and we show this requirement is conserved from C. elegans to Saccharomyces cerevisiae. Our analyses support the idea that cells use eIF5A to identify ribosomal stalls and execute NGD and uncover a molecular function for a core protein synthesis factor in limiting expression from stall-inducing mRNAs. Our work offers insight into how cells identify and remove problematic mRNAs from the translational pool. Our work also raises the possibility that dysregulated mRNA decay is an unrecognized pathophysiology associated with polyaminopathies and eIF5A disorders, of relevance to varied neurodegenerative and aging phenotypes and efforts to pharmacologically inhibit eIF5A.
RNA-binding proteins (RBP) interact with mRNA untranslated regions containing cis-regulatory elements to govern mRNA localization, stability, and translational efficiency. Among these trans-regulatory factors, RNA helicase UPF1 is a central factor which play a role in multiple mRNA decay pathways, including nonsense-mediated mRNA decay (NMD). NMD is triggered when an exon-junction complex (EJC) is located downstream of a premature termination codon. However, in some cases, NMD can be activated in an EJC-independent manner through mechanisms involving the 3'UTR. In the present study, we focused on the GABARAPL1 3'UTR, as previous studies had shown that this region plays a key role in NMD targeting, although the underlying molecular mechanism had not yet been elucidated. Unlike canonical NMD targets such as SC35, we found that the chemical inhibition of eIF4AIII helicase activity did not affect GABARAPL1 transcript levels, indicating that this transcript is regulated through its 3'UTR via an EJC-independent mechanism. We therefore investigated the potential presence of cis-regulatory element within the 3'UTR of GABARAPL1 which can regulate mRNA and protein levels in a UPF1-dependent manner. Furthermore, we identified a conserved RNA region spanning nucleotides 364-421 involved in GABARAPL1 targeting and used biochemical analysis to demonstrate the direct binding of UPF1 and eIF4AIII to this RNA region, to analyse its secondary structure in solution, and to map the protein-binding sites. By complementing these approaches with molecular modelling, we showed that this stem-loop adopts a stable global fold but a local flexibility and dynamic behaviour properties. Together, our results support the role of UPF1 and eIF4AIII as specific regulators of GABARAPL1 transcript and reveal a novel RNA regulatory element within its 3'UTR, which provides a completely unexpected binding site for these factors.
PURPOSE OF REVIEW: Malaria rapid diagnostic tests (RDTs) have revolutionized malaria diagnosis in endemic settings. RDTs are simple to use and accurate for clinical cases, although sensitivity is reduced at parasite densities below 200 parasites/μl. However, increasing prevalence of hrp2/3 gene deletions in certain areas threaten utility of histidine-rich protein 2 (HRP2)-based RDTs, and lingering HRP2 antigenemia can generate false-positive results after parasite clearance. This review summarizes current performance of malaria RDTs, threats to their validity, and recent innovations to improve their performance and continued role in malaria diagnosis. RECENT FINDINGS: Most World Health Organization (WHO) prequalified RDTs perform well for clinical diagnosis, with only occasional exceptions, including a recently reported issue affecting several countries. RDT sensitivity is generally related to malaria transmission intensity, with higher proportions of false-negative results in lower-transmission areas. Newly prequalified lactate dehydrogenase (pLDH)-based RDTs perform well for both Plasmodium falciparum in areas with >5% hrp2/3 gene deletions and for Plasmodium vivax diagnosis. Several point-of-care alternatives to RDTs, including micro-fluidic devices, hemozoin-detecting devices, and automated hematology analyzers, have shown promising results in small studies, but require larger-scale trials before widespread use. SUMMARY: RDTs remain a critical tool in clinical diagnosis of malaria, and newer pLDH-based tests perform well in areas where hrp2/3 gene deletions threaten validity of HRP2-based RDTs.
BACKGROUND: Multiple sclerosis (MS) is a severe neuroinflammatory disease causing substantial long-term disability. Strong epidemiologic evidence links Epstein-Barr virus (EBV) exposure with MS risk, but genetic evidence for immune target prioritization in EBV-related phenotypes remains limited. METHODS: We integrated single-cell cis-eQTL data from 14 immune cell types with GWASs of an EBV-related clinical phenotype and MS using a single-cell Mendelian randomization framework with colocalization analyses. Candidate eGenes were evaluated in independent cohorts. For multi-SNP instruments, we performed heterogeneity, pleiotropy, MR-Egger, weighted median, mode-based, and MR-PRESSO sensitivity analyses. We also conducted phenome-wide association analyses and queried DrugBank to annotate candidate compounds targeting prioritized genes. RESULTS: We prioritized 43 immune-cell-specific candidate eGenes with convergent genetic support, including 6 for the EBV-related phenotype and 37 for MS. SERPINB1 in NK cells was associated with increased risk of the EBV-related phenotype, whereas HLA-G was associated with decreased risk. For MS, APOM and MSH5 showed protective associations, while AHI1 showed cell-type-dependent, bidirectional associations across immune lineages. Colocalization and independent cohort evaluation supported these findings. Among FDR-significant multi-SNP associations, MR-Egger intercept tests did not indicate directional pleiotropy, although a small subset showed heterogeneity or MR-PRESSO signals. Phenome-wide analyses identified no significant adverse phenotypic associations among evaluable genes at the prespecified threshold. DrugBank annotation nominated sodium nitroprusside, fasudil, artenimol, and choline as hypothesis-generating compounds for experimental follow-up. CONCLUSIONS: This study provides a single-cell genetic framework for prioritizing immune-cell-specific candidate targets for EBV-related phenotypes and MS, and nominates genetically supported targets and pharmacologic hypotheses for experimental investigation.
Dysregulation of the epitranscriptomic landscape is closely linked to pathological proliferation, but its specific role in benign prostatic hyperplasia (BPH) remains unclear. Here, we identify the tRNA methyltransferase TRMT61A as a critical driver of BPH progression. We found that TRMT61A and global N1-methyladenosine (m1A) levels are aberrantly upregulated in human BPH tissues. Functionally, TRMT61A knockdown potently suppresses prostate cell proliferation and reduces stromal fibrosis, inducing G1 cell cycle arrest and reversing pathological remodeling both in vitro and in vivo. By integrating ribosome profiling (Ribo-seq) and tRNA-seq, we observed that TRMT61A drives translational reprogramming. TRMT61A preserves the stability of specific tRNA isoacceptors (e.g., tRNA-Leu-CAA), which is required for the efficient decoding of mRNAs containing m1A-dependent codons. Consequently, TRMT61A selectively promotes the translational elongation of the key receptor TGFβR1. This amplifies downstream TGF-β/SMAD signaling and drives epithelial-mesenchymal transition (EMT) without affecting mRNA transcription. In summary, our study reveals how TRMT61A drives BPH progression through TGFβR1 translation, highlighting the therapeutic potential of targeting epitranscriptomic pathways to reverse prostatic hyperplasia and fibrosis.
Fine-resolution information on species relationships and biological diversity is critically needed to guide conservation efforts amidst rapid environmental changes. Systematics, which forms the foundation of this knowledge, has been revolutionized by phylogenomics, utilizing genome-scale datasets. However, the use of diverse marker types, non-comparable taxon sampling, and outgroup selection can lead to conflicting phylogenetic hypotheses. These inconsistencies complicate study comparisons and hinder our ability to assess marker-specific impacts on phylogenetic resolution. The phylogenetic reconstruction of the bat genus Myotis, encompassing over 140 species and characterized by a rapid radiation in the last 20 million years, has been particularly influenced by these challenges. Achieving phylogenetic resolution in Myotis is particularly complex due to subtle interspecific differences in both morphological and molecular traits. Mitochondrial and nuclear markers often produce discordant trees, influenced by hybridization, introgression, and methodological variations. In this study, we employed a consistent taxonomic sample set of 44 Myotis taxa to evaluate the impact of five different genetic marker types on phylogenetic reconstruction. We observed significant discordance between topologies derived from conserved nuclear and mitochondrial markers and found that transposable elements were inadequate for resolving relationships across the entire genus. Our results also clarify the placement of previously problematic taxa within the genus. These findings emphasize the importance of aligning genetic marker choice with specific phylogenetic questions and highlight the influence of taxonomic and methodological variation on phylogenomic outcomes. This work provides a framework for improving phylogenetic inference in rapidly radiating groups and enhances our understanding of evolutionary history in Myotis.
Buffaloes do not exhibit overt estrus signs particularly during summer, leading to a significant economic loss to farmers. Previous studies have identified several candidate transcripts (HSP70, TIMP1, TLR4 and HSD17B1), abundant in buffalo saliva during estrus stage. However, there is no widely applicable technology for estrus detection targeting these transcripts. Therefore, the present study aimed to develop reverse transcription loop mediated isothermal amplification (RT-LAMP) assays for these candidate transcripts using buffalo saliva. Saliva samples were collected from 10 cyclic buffaloes and RT-LAMP assays were optimized for salivary RNA as well as direct saliva. Among the four candidate transcripts, HSP70 showed a statistically significant colour change (p-value = 0.0191) at the estrus stage compared to the diestrus stage. This abundance of HSP70 was also supported in large simulated population datasets (10,000 animals) generated using R. Further, the RT-LAMP assays were tested using direct saliva without RNA isolation, and the colour change in the samples during estrus suggested the feasibility of estrus identification using direct saliva, overcoming the tedious step of RNA isolation. The detection of HSP70 using either direct saliva or salivary RNA indicated its potential as a marker for estrus identification. Similarly, TLR4 appeared to be another potential biomarker for RT-LAMP reaction using direct saliva, but it needs further validation in both RNA and direct saliva samples. Overall, the proof-of-concept on RT-LAMP assays optimized for salivary transcripts in the present study would be useful for estrus identification in tropical production systems following further validation on a larger sample size.
Ribosomes can pause during mRNA translation, but what causes pausing, how pauses affect protein production, and whether they trigger cotranslational mRNA decay are poorly understood in plants. Here, we investigate the causes and consequences of ribosome pausing in Arabidopsis and maize. This is accomplished by sizing, mapping, and quantifying footprints of individual ribosomes (monosomes) and closely spaced ribosome pairs (disomes) at single-codon resolution on open reading frames (ORFs). Ribosome footprinting was combined with 5'P-degradome-seq to examine the coincidence of pausing with cotranslational decay under control conditions and brief hypoxia in Arabidopsis. The data resolve two monosome conformations and three disome configurations. These include monosomes with a vacant or occupied A-site and disomes that have collided or are separated by one or two codons. Pausing is prevalent at initiation, termination, and di-Proline codons. Di-Proline pauses do not trigger cotranslational decay but appear important in cotranslational protein processing. Brief hypoxia induces stalling of A-site vacant ribosomes at Aspartate codons, often coinciding with 5'P peaks, indicating that rate-limiting decoding can trigger cotranslational mRNA decay. Notably, actively transcribed and translated hypoxia-response mRNAs accumulate 1- to 2-codon-separated disomes and are actively degraded. Comparative analysis of footprints in the two species reveals ribosome conformations and codon-specific pausing can be conserved or lineage-specific, as exemplified by pausing at di-Prolines and on Conserved Peptide upstream ORFs. In sum, the stalling of ribosomes at specific codons, coupled with ribosome A-site occupancy and disome spacing, modulates protein production and cotranslational mRNA decay in plants.
About one hundred subterranean catfish species have been described, resulting from repeated colonization of cave environments by multiple surface lineages. Most cave-dwelling species are found in the Americas, in particular in South America, but a few species also live in Central and North America. Despite the availability of high-quality genome assemblies for two cave species, the Mexican blind catfish Prietella phreatophila and the Colombian blind catfish Trichomycterus rosablanca, genomic approaches to investigate genetic changes associated with subterranean life or to estimate cave colonization times remain largely unexplored. To fill this gap, we additionally sequenced the genomes of four blind and depigmented subterranean catfishes from Peru (three Trichomycterus and one Astroblepus), as well as the genomes of four close surface relatives. We first extracted a large set of light-related genes, such as phototransduction and crystallin genes, and found contrasting decays of these sequences in different cave species, from 1% of pseudogenes in T. rosablanca to 48% in P. phreatophila. Two independent molecular dating methods gave congruent ages, indicating that these catfishes colonized subterranean habitats at different times, ranging from Early Pliocene to Late Pleistocene, supporting the hypothesis that surface catfishes repeatedly and rapidly adapted to subterranean habitats. The oldest cave species, P. phreatophila, appears to have been thriving in the dark for over 3.5 million years. Moreover, a genome-wide analysis of protein-coding genes suggests weaker purifying selection on mildly deleterious mutations in this cavefish than in other catfish lineages, likely reflecting a long-term small effective population size.