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Open Biology Nov 2023Eukaryotic pre-mRNA is processed by a large multiprotein complex to accurately cleave the 3' end, and to catalyse the addition of the poly(A) tail. Within this cleavage...
Eukaryotic pre-mRNA is processed by a large multiprotein complex to accurately cleave the 3' end, and to catalyse the addition of the poly(A) tail. Within this cleavage and polyadenylation specificity factor (CPSF) machinery, the CPSF73/CPSF3 endonuclease subunit directly contacts both CPSF100/CPSF2 and the scaffold protein Symplekin to form a subcomplex known as the core cleavage complex or mammalian cleavage factor. Here we have taken advantage of a stable CPSF73-CPSF100 minimal heterodimer from to determine the solution structure formed by the first and second C-terminal domain (CTD1 and CTD2) of both proteins. We find a large number of contacts between both proteins in the complex, and notably in the region between CTD1 and CTD2. A similarity is also observed between CTD2 and the TATA-box binding protein (TBP) domains. Separately, we have determined the structure of the terminal CTD3 domain of CPSF73, which also belongs to the TBP domain family and is connected by a flexible linker to the rest of CPSF73. Biochemical assays demonstrate a key role for the CTD3 of CPSF73 in binding Symplekin, and structural models of the trimeric complex from other species allow for comparative analysis and support an overall conserved architecture.
Topics: Cleavage And Polyadenylation Specificity Factor; mRNA Cleavage and Polyadenylation Factors; Encephalitozoon cuniculi
PubMed: 37989222
DOI: 10.1098/rsob.230221 -
Molecular Biology and Evolution Jan 2024Ribosomes from different species can markedly differ in their composition by including dozens of ribosomal proteins that are unique to specific lineages but absent in...
Ribosomes from different species can markedly differ in their composition by including dozens of ribosomal proteins that are unique to specific lineages but absent in others. However, it remains unknown how ribosomes acquire new proteins throughout evolution. Here, to help answer this question, we describe the evolution of the ribosomal protein msL1/msL2 that was recently found in ribosomes from the parasitic microorganism clade, microsporidia. We show that this protein has a conserved location in the ribosome but entirely dissimilar structures in different organisms: in each of the analyzed species, msL1/msL2 exhibits an altered secondary structure, an inverted orientation of the N-termini and C-termini on the ribosomal binding surface, and a completely transformed 3D fold. We then show that this fold switching is likely caused by changes in the ribosomal msL1/msL2-binding site, specifically, by variations in rRNA. These observations allow us to infer an evolutionary scenario in which a small, positively charged, de novo-born unfolded protein was first captured by rRNA to become part of the ribosome and subsequently underwent complete fold switching to optimize its binding to its evolving ribosomal binding site. Overall, our work provides a striking example of how a protein can switch its fold in the context of a complex biological assembly, while retaining its specificity for its molecular partner. This finding will help us better understand the origin and evolution of new protein components of complex molecular assemblies-thereby enhancing our ability to engineer biological molecules, identify protein homologs, and peer into the history of life on Earth.
Topics: Animals; Ribosomal Proteins; Ribosomes; RNA, Ribosomal; Binding Sites; Parasites
PubMed: 37987564
DOI: 10.1093/molbev/msad254 -
EMBO Reports Dec 2023Disrupting the small RNA pathway and chromatin-modifying enzymes in C. elegans often leads to a mortal germline (Mrt) phenotype, characterized by progressive sterility...
Disrupting the small RNA pathway and chromatin-modifying enzymes in C. elegans often leads to a mortal germline (Mrt) phenotype, characterized by progressive sterility observed over multiple generations at elevated temperature. This phenotype arises from the inheritance of aberrant epigenetic memory across generations. In this issue of EMBO Reports, Frézal and colleagues reported that, while in standard laboratory environment C. elegans wild isolates exhibit the Mrt phenotype, sterility does not occur when the worms are exposed to naturally associated bacteria and microsporidia. Excitingly, diet-induced epigenetic memory may persist for multiple generations. This suggests intriguing diet-gene interactions in modulating nongenetic inheritance, potentially shaping the evolutionary trajectory of the animals.
Topics: Animals; Caenorhabditis elegans; Epigenesis, Genetic; Caenorhabditis elegans Proteins; Phenotype; Infertility
PubMed: 37983676
DOI: 10.15252/embr.202358318 -
EMBO Reports Dec 2023The animal germline lineage needs to be maintained along generations. However, some Caenorhabditis elegans wild isolates display a mortal germline phenotype, leading to...
The animal germline lineage needs to be maintained along generations. However, some Caenorhabditis elegans wild isolates display a mortal germline phenotype, leading to sterility after several generations at 25°C. Using a genome-wide association approach, we detect a significant peak on chromosome III around 5 Mb, confirmed by introgressions. Thus, a seemingly deleterious genotype is maintained at intermediate frequency in the species. Environmental rescue is a likely explanation, and indeed associated bacteria and microsporidia suppress the phenotype of wild isolates as well as mutants in small RNA inheritance (nrde-2) and histone modifications (set-2). Escherichia coli strains of the K-12 lineage suppress the phenotype compared to B strains. By shifting a wild strain from E. coli K-12 to E. coli B, we find that memory of the suppressing condition is maintained over several generations. Thus, the mortal germline phenotype of wild C. elegans is in part revealed by laboratory conditions and may represent variation in epigenetic inheritance and environmental interactions. This study also points to the importance of non-genetic memory in the face of environmental variation.
Topics: Animals; Caenorhabditis elegans; Escherichia coli; Genome-Wide Association Study; Phenotype; Germ Cells; Caenorhabditis elegans Proteins
PubMed: 37983674
DOI: 10.15252/embr.202358116 -
Parasitology Jan 2024Recent outbreaks of various infectious diseases have highlighted the ever-present need to understand the drivers of the outbreak and spread of disease. Although much of...
Recent outbreaks of various infectious diseases have highlighted the ever-present need to understand the drivers of the outbreak and spread of disease. Although much of the research investigating diseases focuses on single infections, natural systems are dominated by multiple infections. These infections may occur simultaneously, but are often acquired sequentially, which may alter the outcome of infection. Using waterfleas () as a model organism, we examined the outcome of sequential and simultaneous multiple infections with 2 microsporidian parasites ( and ) in a fully factorial design with 9 treatments and 30 replicates. We found no differences between simultaneous and sequential infections. However, fitness was impeded by multiple infection due to increased host mortality, which gave less time to grow. Host fecundity was also reduced across all treatments, but animals infected with at a younger age produced the fewest offspring. As is both horizontally and vertically transmitted, this reduction in offspring may have further reduced fitness in co-infected treatments. Our findings suggest that in natural populations where both species co-occur, may evolve to higher levels of virulence following frequent co-infection by .
Topics: Animals; Parasites; Daphnia; Virulence; Microsporidia; Host-Parasite Interactions
PubMed: 37981808
DOI: 10.1017/S0031182023001130 -
Scientific Reports Nov 2023Microsporidia are obligate intracellular parasites that lost several enzymes required in energy production. The expansion of transporter families in these organisms...
Microsporidia are obligate intracellular parasites that lost several enzymes required in energy production. The expansion of transporter families in these organisms enables them to hijack ATP from hosts. In this study, nucleotide transporters of the microsporidian Enterocytozoon hepatopenaei (EHP), which causes slow growth in economically valuable Penaeus shrimp, were characterized. Analysis of the EHP genome suggested the presence of four putative nucleotide transporter genes, namely EhNTT1, EhNTT2, EhNTT3, and EhNTT4. Sequence alignment revealed four charged amino acids that are conserved in previously characterized nucleotide transporters. Phylogenetic analysis suggested that EhNTT1, 3, and 4 were derived from one horizontal gene transfer event, which was independent from that of EhNTT2. Localization of EhNTT1 and EhNTT2 using immunofluorescence analysis revealed positive signals within the envelope of developing plasmodia and on mature spores. Knockdown of EhNTT2 by double administration of sequence specific double-stranded RNA resulted in a significant reduction in EHP copy numbers, suggesting that EhNTT2 is crucial for EHP replication in shrimp. Taken together, the insight into the roles of NTTs in microsporidian proliferation can provide the biological basis for the development of alternative control strategies for microsporidian infection in shrimp.
Topics: Animals; Microsporidia; Nucleotides; Phylogeny; Enterocytozoon; Penaeidae
PubMed: 37974017
DOI: 10.1038/s41598-023-47114-8 -
BMC Microbiology Nov 2023Enterocytozoon bieneusi, Encephalitozoon spp., Cryptosporidium spp., and Giardia duodenalis (G. intestinalis) are enteric pathogens that cause diarrhea in pigs. This...
First identification and coinfection detection of Enterocytozoon bieneusi, Encephalitozoon spp., Cryptosporidium spp. and Giardia duodenalis in diarrheic pigs in Southwest China.
BACKGROUND
Enterocytozoon bieneusi, Encephalitozoon spp., Cryptosporidium spp., and Giardia duodenalis (G. intestinalis) are enteric pathogens that cause diarrhea in pigs. This study aimed to determine the prevalence of these enteric parasites and their coinfection with E. bieneusi in diarrheic pigs in Southwest China (Chongqing and Sichuan) using nested polymerase chain reaction (nPCR) based methods.
RESULTS
A total of 514 fecal samples were collected from diarrheic pigs from 14 pig farms in Chongqing (five farms) and Sichuan (nine farms) Provinces. The prevalence of Encephalitozoon spp., Cryptosporidium spp. and G. duodenalis was 16.14% (83/514), 0% (0/514), and 8.95% (46/514), respectively. Nested PCR revealed 305 mono-infections of E. bieneusi, six of E. cuniculi, two of E. hellem, and nine of G. duodenalis and 106 concurrent infections of E. bieneusi with the other enteric pathogens. No infections of E. intestinalis and Cryptosporidium species were detected. The highest coinfection was detected between E. bieneusi and E. cuniculi (10.5%, 54/514), followed by E. bieneusi and G. duodenalis (5.8%, 30/514) and E. bieneusi and E. hellem (2.9%, 15/514). E. bieneusi was the most frequently detected enteric pathogen, followed by E. cuniculi, G. duodenalis and E. hellem. There was a significant age-related difference in the prevalence of E. cuniculi in fattening pigs (χ = 15.266, df = 3, P = 0.002) and G. duodenalis in suckling pigs (χ = 11.92, df = 3, P = 0.008) compared with the other age groups. Sequence analysis of the ITS region of Encephalitozoon species showed two genotypes (II and III) for E. cuniculi and one (TURK1B) for E. hellem. Only G. duodenalis assemblage A was identified in all nested PCR-positive samples. E. bieneusi was found more often than other enteric pathogens.
CONCLUSIONS
This study showed that E. bieneusi, Encephalitozoon spp. [E. cuniculi and E. hellem] and G. duodenalis were common enteric parasites in diarrheic pigs in Chongqing and Sichuan Provinces. In case of both mono-infection and coinfection, E. bieneusi was the most common enteric pathogen in diarrheic pigs. Thus, it may be a significant cause of diarrhea in pigs. Precautions should be taken to prevent the spread of these enteric parasites.
Topics: Animals; Swine; Giardia lamblia; Giardiasis; Enterocytozoon; Cryptosporidiosis; Cryptosporidium; Encephalitozoon; Coinfection; Microsporidiosis; China; Genotype; Feces; Diarrhea
PubMed: 37951859
DOI: 10.1186/s12866-023-03070-x -
BMC Infectious Diseases Nov 2023Most cases of microsporidial keratoconjunctivitis are found in the Southern hemisphere. Our purpose was to investigate the first outbreak of microsporidial... (Observational Study)
Observational Study
BACKGROUND
Most cases of microsporidial keratoconjunctivitis are found in the Southern hemisphere. Our purpose was to investigate the first outbreak of microsporidial keratoconjunctivitis in Japan among healthy, immunocompetent soccer players from the same team during a 1-month period.
CASE PRESENTATION
This study is an observational case series. The medical records were analyzed for five cases with microsporidial keratoconjunctivitis who presented within September 2022. All five cases were males between 28 and 36 years old. These previously healthy individuals belonged to the same football team. Their eyes were considered susceptible to contaminated water or dirt from the turf at game and practice sites. All cases involved unilateral conjunctivitis, with scattered round white lesions that showed positive fluorescein staining in the corneal epithelium. All cases experienced diminution of vision in the affected eye. In three cases, direct smears showed spores of approximately 2-3 μm in diameter. Polymerase chain reaction (PCR) analysis of corneal scrapes revealed partial amplification of microsporidial 18 S ribosomal RNA gene in four cases. Sequences of PCR products from all four cases showed 100% identity with strains of Vittaforma corneae previously reported from an outbreak in Singapore. All cases were treated with topical therapy, including voriconazole, fluorometholone, and levofloxacin. Four eyes underwent corneal scraping. After treatment, all eyes healed without residual opacities.
CONCLUSIONS
Only a few sporadic case reports of this disease have previously been reported in Japan. We detected V. corneae in our case series, representing what appears to be the first outbreak of microsporidial keratoconjunctivitis in Japan. Exposure to contaminated water or soil, in addition to inadequate sanitary facilities, represents a potential source of infection. Further investigations to clarify the characteristics of microsporidia seem warranted.
Topics: Male; Humans; Adult; Female; Microsporidiosis; Japan; Keratoconjunctivitis; Disease Outbreaks; Water
PubMed: 37915107
DOI: 10.1186/s12879-023-08767-y -
Life Science Alliance Jan 2024During the reductive evolution of obligate intracellular parasites called microsporidia, a tiny remnant mitochondrion (mitosome) lost its typical cristae, organellar...
During the reductive evolution of obligate intracellular parasites called microsporidia, a tiny remnant mitochondrion (mitosome) lost its typical cristae, organellar genome, and most canonical functions. Here, we combine electron tomography, stereology, immunofluorescence microscopy, and bioinformatics to characterise mechanisms of growth, division, and inheritance of this minimal mitochondrion in two microsporidia species (grown within a mammalian RK13 culture-cell host). Mitosomes of (2-12/cell) and (14-18/nucleus) displayed incremental/non-phasic growth and division and were closely associated with an organelle identified as equivalent to the fungal microtubule-organising centre (microsporidian spindle pole body; mSPB). The mitosome-mSPB association was resistant to treatment with microtubule-depolymerising drugs nocodazole and albendazole. Dynamin inhibitors (dynasore and Mdivi-1) arrested mitosome division but not growth, whereas bioinformatics revealed putative dynamins Drp-1 and Vps-1, of which, Vps-1 rescued mitochondrial constriction in dynamin-deficient yeast (). Thus, microsporidian mitosomes undergo incremental growth and dynamin-mediated division and are maintained through ordered inheritance, likely mediated via binding to the microsporidian centrosome (mSPB).
Topics: Animals; Fungal Proteins; Mitochondria; Microsporidia; Saccharomyces cerevisiae; Dynamins; Mammals
PubMed: 37903625
DOI: 10.26508/lsa.202201635 -
Animals : An Open Access Journal From... Jun 2023and spp. are microsporidian pathogens with zoonotic potential that pose significant public health concerns. To ascertain the occurrence and genotypes of and spp., we...
and spp. are microsporidian pathogens with zoonotic potential that pose significant public health concerns. To ascertain the occurrence and genotypes of and spp., we used nested PCR to amplify the internal transcribed spacer (ITS) gene and DNA sequencing to analyze 198 fecal samples from red pandas from 6 zoos in China. The total rate of microsporidial infection was 15.7% (31/198), with 12.1% (24/198), 1.0% (2/198), 2.0% (4/198) and 1.0% (2/198) for infection rate of , , and , respectively. One red panda was detected positive for a mixed infection ( and ). Red pandas living in semi-free conditions are more likely to be infected with microsporidia (χ = 6.212, df = 1, < 0.05). Three known (SC02, D, and PL2) and one novel (SCR1) genotypes of were found. Three genotypes of (SC02, D, SCR1) were grouped into group 1 with public health importance, while genotype PL2 formed a separate clade associated with group 2. These findings suggest that red pandas may serve as a host reservoir for zoonotic microsporidia, potentially allowing transmission from red pandas to humans and other animals.
PubMed: 37889781
DOI: 10.3390/ani13111864