Project description:Gene silencing mediated by dsRNA (RNAi) can persist for multiple generations in C. elegans (termed RNAi inheritance). Here we describe the results of a forward genetic screen in C. elegans that has identified six factors required for RNAi inheritance: GLH-1/VASA, PUP-1/CDE-1, MORC-1, SET-32, and two novel nematode-specific factors that we term here (heritable RNAi defective) HRDE-2 and HRDE-4. The new RNAi inheritance factors exhibit mortal germline (Mrt) phenotypes, which we show is likely caused by epigenetic deregulation in germ cells. We also show that HRDE-2 contributes to RNAi inheritance by facilitating the binding of small RNAs to the inheritance Argonaute (Ago) HRDE-1. Together, our results identify additional components of the RNAi inheritance machinery whose sequence conservation provides insights into the molecular mechanism of RNAi inheritance, further our understanding of how the RNAi inheritance machinery promotes germline immortality, and show that HRDE-2 couples the inheritance Ago HRDE-1 with the small RNAs it needs to direct RNAi inheritance and germline immortality.
Project description:Maize plants were transformed with endosperm-specific PPDK RNAi knockout constructs to alter starch/protein ratios. Metabolite pool comparisons will be examined from sibling kernels harvested from segregating ears.
Project description:The RNA interference (RNAi) pathway is found in most eukaryotic lineages but curiously is absent in others, including that of Saccharomyces cerevisiae. Here, we show that reconstituting RNAi in S. cerevisiae causes loss of a beneficial dsRNA virus, known as killer virus. Incompatibility between RNAi and killer viruses extends to other fungal species, in that RNAi is absent in all species known to possess dsRNA killer viruses, whereas killer viruses are absent in closely related species that retained RNAi. Thus, the advantage imparted by acquiring and retaining killer viruses explains the persistence of RNAi-deficient species during fungal evolution.
Project description:The RNA interference (RNAi) pathway has evolved numerous functionalities in eukaryotes, with many on display in Kingdom Fungi. RNAi can regulate gene expression, facilitate drug resistance, or even be altogether lost to improve virulence potential in some fungal pathogens. In the WHO fungal priority pathogen, Aspergillus fumigatus, the RNAi system is known to be intact and functional. To extend our limited understanding of A. fumigatus RNAi, we performed a multi-condition sRNA-seq analysis comparing expression of several RNAi double knockout mutants with the wild-type strain in conidia and mycelium grown for 24 or 48 hours.
Project description:ApoB-1 and ApoB-2 are intestine-enriched regulators of lipoprotein secretion in planarians. The goal of this study was to identify differentially expressed transcripts in uninjured apob-1(RNAi);apob-2(RNAi) double knockdown planarians relative to egfp(RNAi) control animals.
Project description:RNAi-elicited gene silencing is heritable and can persist for multiple generations after its initial induction in C. elegans. However, the mechanism by which parental-acquired trait-specific information from RNAi is inherited by the progenies is not fully understood. Here, we identified a cytoplasmic Argonaute protein, WAGO-4, necessary for the inheritance of RNAi. WAGO-4 exhibits asymmetrical translocation to the germline during early embryogenesis, accumulates at the perinuclear foci in the germline, and is required for the inheritance of exogenous RNAi targeting both germline- and soma-expressed genes. WAGO-4 binds to 22G-RNA and its mRNA targets. Interestingly, WAGO-4-associated endogenous 22G-RNA targets the same cohort of germline genes as CSR-1 and similarly contains untemplated addition of uracil at the 3' ends. The poly(U) polymerase CDE-1 is required for the untemplated polyuridylation of WAGO-4-associated 22G-RNAs and inheritance of RNAi. Therefore, we conclude that the cytoplasmic Argonaute protein WAGO-4 also promotes the inheritance of RNAi in addition to the nuclear RNAi pathway.