Project description:The Piwi-piRNA pathway represents a germline specific transposon-defense system. C. elegans Piwi, prg-1, is a non-essential gene and triggers a secondary RNAi response that depends on so-called mutator genes, endo-siRNAs (22G-RNAs) and at least one 22G-RNA-binding Argonaute protein, HRDE-1. Interestingly, through a poorly understood mechanism, silencing of PRG-1 targets can become PRG-1 independent. This state, also known as RNAe, is heritable and depends on mutator genes and HRDE-1. We studied how the transgenerational memory of RNAe and the piRNA pathway interact. We find that maternally provided PRG-1 is required for the de-novo establishment of 22G-RNA populations, especially those targeting transposons. Strikingly, attempts to re-establish 22G-RNAs in absence of both PRG-1 and RNAe memory result in severe germline proliferation defects. This is accompanied by a disturbed balance between gene-activating and -repressing 22G-RNA pathways. We propose a model in which CSR-1 prevents the loading of HRDE-1 and that both PRG-1 and HRDE-1 help to keep mutator activity focused on the proper targets.
Project description:Piwi-related Argonaute proteins play important roles in maintaining germline integrity and fertility and have been linked to a class of germline-enriched small RNAs termed piRNAs. Caenorhabditis elegans encodes two Piwi family proteins called PRG-1 and PRG-2, and PRG-1 interacts with the C. elegans piRNAs (21U-RNAs). Previous studies found that the prg-1 mutation causes a marked reduction in the expression of 21U-RNAs, temperature-sensitive defects in fertility and other phenotypic defects.To systematically demonstrate the function of PRG-1 on regulating small RNAs and their targets. We use recent advances in high-throughput sequencing technology to show that expression of non-coding small RNAs in six stages(embryo,L1,L2,L3,L4,young audlt) and mRNAs in four stages (L1,L2,L3,L4) after prg-1 mutation. prg-1 mutation can not only lead to a decrease in the expression of 21U-RNAs, but also cause 35~40% of miRNAs to be significantly down-regulated; approximately 3% (6.00% in L4) of protein-coding genes are differentially expressed after mutating prg-1, and 60~70% of these substantially changed protein-coding genes are up-regulated.
Project description:Investigation of whole genome gene expression level changes in early generation Caenorhabditis elegans Bristol N2 prg-1 and Bristol N2 prg-1; daf-2 double mutant, compared to late-generation strains. A seven chip study using total RNA recovered from three separate alleles of Caenorhabditis elegans Bristol N2 prg-1 and four separate allelic combinations of a double mutant strain, Bristol N2 prg-1; daf-2 , in which prg-1 (pk2298) and prg-1 (tm872) are combined with one of three daf-2 alleles (e1368, 1370, m41).
Project description:Piwi-related Argonaute proteins play important roles in maintaining germline integrity and fertility and have been linked to a class of germline-enriched small RNAs termed piRNAs. Caenorhabditis elegans encodes two Piwi family proteins called PRG-1 and PRG-2, and PRG-1 interacts with the C. elegans piRNAs (21U-RNAs). Previous studies found that the prg-1 mutation causes a marked reduction in the expression of 21U-RNAs, temperature-sensitive defects in fertility and other phenotypic defects.To systematically demonstrate the function of PRG-1 on regulating small RNAs and their targets. We use recent advances in high-throughput sequencing technology to show that expression of non-coding small RNAs in six stages(embryo,L1,L2,L3,L4,young audlt) and mRNAs in four stages (L1,L2,L3,L4) after prg-1 mutation. prg-1 mutation can not only lead to a decrease in the expression of 21U-RNAs, but also cause 35~40% of miRNAs to be significantly down-regulated; approximately 3% (6.00% in L4) of protein-coding genes are differentially expressed after mutating prg-1, and 60~70% of these substantially changed protein-coding genes are up-regulated.