Dynamic Control of Argonautes by a Rapidly Evolving Immunological Switch
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PROVIDER: PRJNA1194973 | ENA |
REPOSITORIES: ENA
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Project description:Small RNAs, coupled with Argonuate proteins (AGOs), regulate diverse biological processes, including immunity against parasitic genetic elements. C. elegans possesses an expanded repertoire of at least 19 AGOs functioning in an intricate gene regulatory network. Despite their crucial roles, little is known about the regulation of AGOs, and whether their expression levels, tissue specificity, and functions change in response to genetic perturbations or environmental triggers. Here, we report that PALS-22, a member of an unusually expanded protein family in C. elegans, acts as a negative regulator of antiviral RNAi involving the RIG-I homolog. The loss of pals-22 leads to enhanced silencing of transgenes and endogenous dsRNAs. We found that PALS-22 normally suppresses the expression of two AGOs, VSRA-1 and SAGO-2, which are activated by bZIP transcription factor ZIP-1. When pals-22 is eliminated, vsra-1 and sago-2 are upregulated. These AGOs in turn play key roles in defense against foreign genetic elements and intracellular pathogens, respectively. Surprisingly, while in pals-22 mutants immune genes functioning in the intracellular pathogen response (IPR) are upregulated, removing SAGO-2 or the RNA-dependent RNA polymerase RRF-3 in these mutants leads to the downregulation of these genes. This observation contrasts with the typical gene-silencing role of siRNAs. Finally, by analyzing C. elegans wild isolates and lab reference strains, we demonstrate that PALS-22 regulates the expression of several germline AGOs, affecting germline mortality and transgenerational epigenetic inheritance. In summary, PALS-22 is a key genetic node that balances the trade-off between immunity and germline health by modulating the functions of different AGOs, thereby shaping the outputs of the RNAi machinery and the dynamics of epigenetic inheritance.
2025-05-11 | GSE283649 | GEO
Project description:The Genetic Basis of Rapidly Evolving Male Genital Morphology in Drosophila
| PRJNA138869 | ENA
Project description:Background: Studying genomic variation in rapidly evolving pathogens potentially enables definition of genes supporting their “core biology” present, functional and expressed by all strains or “flexible biology”, varying between strains. Genes supporting flexible biology may be considered to be “accessory”, whilst the “core” gene set is likely to be important for common features of a pathogen species biology, including virulence on all host genotypes. The wheat-pathogenic fungus Zymoseptoria tritici represents one of the most rapidly evolving threats to global food security and was the focus of this study. Results:We constructed a pangenome of 18 European field isolates, with 12 also subjected to RNAseq transcription profiling during infection. Combining this data, we predicted a “core” gene set comprising 9807 sequences which were; (1) present in all isolates; (2) lacking inactivating polymorphisms ; and (3) expressed by all isolates. A large accessory genome, consisting of 45% of the total genes was also defined. We classified genetic and genomic polymorphism at both chromosomal and individual gene scales. Proteins required for essential functions including virulence, had lower-than average sequence variability amongst core genes. Both core and accessory genomes encoded many small, secreted candidate effector proteins that likely interact with plant immunity. Viral vector-mediated transient in planta overexpression of 88 candidates failed to identify any which induced leaf necrosis characteristic of disease. However, functional complementation of a non-pathogenic deletion mutant lacking five core genes, demonstrated that full virulence was restored by re-introduction of the single gene exhibiting least sequence polymorphism and highest expression. Conclusions:These data support the combined use of pangenomics and transcriptomics for defining genes which represent core, and potentially exploitable, weaknesses in rapidly evolving pathogens.
2023-01-13 | GSE222164 | GEO
Project description:Antiviral function and viral antagonism of the rapidly evolving dynein activating adapter NINL
| PRJNA852187 | ENA
Project description:We performed Immuno precipitation using antibodies against Nematostella vectensis Argonauts proteins (i.e AGO1 and AGO2). Samples of the IP were analyzed by LC-MSMS in order to idetify the argonautes and prove antibodies specifity.
2020-10-14 | PXD011644 | Pride
Project description:Two novel, tightly linked, and rapidly evolving genes underlie Aedes aegypti mosquito reproductive resilience during drought
| PRJNA796320 | ENA
Project description:Female Aedes aegypti mosquitoes impose a severe global public health burden as primary vectors of multiple viral and parasitic pathogens. Under optimal environmental conditions, Aedes aegypti females have access to human hosts that provide blood proteins for egg development, conspecific males that provide sperm for fertilization, and freshwater that serves as an egg-laying substrate suitable for offspring survival. As global temperatures rise, Aedes aegypti females are faced with climate challenges, like intense droughts and intermittent precipitation, which create unpredictable and suboptimal conditions for the egg-laying step of their reproductive cycle. Aedes aegypti mosquitoes nonetheless show remarkable reproductive resilience, but how they achieve this is unknown. Here we show that under drought-like conditions simulated in the laboratory, mated, blood-fed Aedes aegypti females carrying mature eggs retain them in their ovaries for extended periods, while maintaining the viability of these eggs until they can be deposited in freshwater. Using transcriptomic and proteomic profiling of Aedes aegypti ovaries, we identify two previously uncharacterized genes – here named tweedledee and tweedledum – that show ovary-enriched, temporally-restricted expression during egg retention. These genes are mosquito-specific, linked within a syntenic locus, and rapidly evolving under positive selection, raising the possibility that they serve an adaptive function. Using loss-of-function mutagenesis to disrupt both genes, we show that, tweedledee and tweedledum, which encode secreted proteins, are specifically required for extended retention of viable eggs, such as during intermittent precipitation or drought. These results highlight an elegant example of taxon-restricted genes at the heart of an important adaptation that equips Aedes aegypti females with “insurance” to, when contextually appropriate, flexibly extend their reproductive sequence without losing reproductive capacity, thus allowing this species to exploit diverse and unpredictable/chaotic/changing habitats.
2022-03-02 | PXD030925 | Pride
Project description:Combined pangenomics and transcriptomics reveals core and redundant virulence processes in a rapidly evolving fungal plant pathogen
| PRJNA918399 | ENA
Project description:microRNAs regulate gene expression through interaction with an Argonaute protein family member. While some members of this protein family retain an enzymatic activity capable of cleaving RNA molecules complementary to Argonaute-bound small RNAs, the role of the slicing activity in the canonical microRNA pathway is still unclear in animals. To address the importance of slicing Argonautes in animals, we created Caenorhabditis elegans mutant strains carrying catalytically dead endogenous ALG-1 and ALG-2, the only two slicing Argonautes essential for the miRNA pathway in this animal model. We observe that the loss of ALG-1 and ALG-2 slicing activity affects overall animal fitness and causes phenotypes reminiscent of miRNA defects only when grown and maintained at restrictive temperature. Furthermore, the analysis of global miRNA expression show that the catalytic activity of ALG-1 and ALG-2 differentially regulate the level of specific subsets of miRNAs in young adults. We also demonstrate that altering the slicing activity of those miRNA-specific Argonautes does not result in any defect in the production of canonical miRNAs. Together, these data support that the slicing activity of miRNA-specific Argonautes functions to maintain levels of a set of miRNAs for optimal viability and fitness in animals particularly exposed to specific growing conditions.
2024-03-15 | GSE222733 | GEO