Project description:To determine how the mtDNA load at the beginning of tumorigenesis affects the DNA methylation patterns of TRFs during tumourigenesis. Different loads of mtDNA at the beginning of tumourigenesis have limited impact on the copy number variation contributing to tumorigenesis.
Project description:How mitochondrial DNA (mtDNA) polymorphisms influence complex phenotypes remains poorly understood. Using Mitochondrial-Nuclear eXchange (MNX) mice, we previously showed that mtDNA single nucleotide polymorphisms (SNP) modify metastasis, cardiovascular disease, and epigenetic marks independently of metabolic differences, suggesting a role for non-protein-coding loci. The only SNP correlating with these phenotypes resides in the gene encoding mitochondrial tRNA-Arginine (mt-tRNAArg (UCG), mt-TR). Here we identify and preliminarily characterize previously undescribed tRNA-derived fragments (tRF) generated from mt-TR. Northern blotting revealed distinct tRF that are differentially expressed between lung and liver and between sexes. Small RNA sequencing failed to capture these tRF unless samples were pre-treated to enzymatically remove non-canonical RNA termini and base methylation. Focusing on fragments with complete homology to mt-TR, the two most abundant tRF align uniquely to the mitochondrial genome and share conserved cleavage sites. Together, these findings uncover mitochondrial-derived tRF as a previously unrecognized small RNA metastasis modifiers and expand the functional output of the mitochondrial genome, supporting a model in which mtDNA-encoded tRF contribute to phenotype modification.
Project description:How mitochondrial DNA (mtDNA) polymorphisms influence complex phenotypes remains poorly understood. Using Mitochondrial-Nuclear eXchange (MNX) mice, we previously showed that mtDNA single nucleotide polymorphisms (SNP) modify metastasis, cardiovascular disease, and epigenetic marks independently of metabolic differences, suggesting a role for non-protein-coding loci. The only SNP correlating with these phenotypes resides in the gene encoding mitochondrial tRNA-Arginine (mt-tRNAArg (UCG), mt-TR). Here we identify and preliminarily characterize previously undescribed tRNA-derived fragments (tRF) generated from mt-TR. Northern blotting revealed distinct tRF that are differentially expressed between lung and liver and between sexes. Small RNA sequencing failed to capture these tRF unless samples were pre-treated to enzymatically remove non-canonical RNA termini and base methylation. Focusing on fragments with complete homology to mt-TR, the two most abundant tRF align uniquely to the mitochondrial genome and share conserved cleavage sites. Together, these findings uncover mitochondrial-derived tRF as a previously unrecognized small RNA metastasis modifiers and expand the functional output of the mitochondrial genome, supporting a model in which mtDNA-encoded tRF contribute to phenotype modification.
Project description:Maternal inheritance of mitochondrial DNA (mtDNA) is highly conserved in metazoans. While many species eliminate paternal mtDNA during late sperm development to foster maternal inheritance, the regulatory mechanisms governing this process remain elusive. Through a large-scale genetic screen in Drosophila, we identified 47 mutant lines exhibiting substantial retention of mtDNA in mature sperm. We mapped one line to Poldip2, a gene predominantly expressed in the testis. Disruption of Poldip2 led to pronounced mtDNA retention in mature sperm and subsequent paternal transmission to progeny. Further investigation via imaging, biochemical analyses and ChIP assays revealed that POLDIP2 is a mitochondrial matrix protein capable of binding to mtDNA. Moreover, we uncovered that CLPX, a key component of the major mitochondrial protease, binds to POLDIP2 to co-regulate mtDNA elimination in Drosophila spermatids. This study shed light on the mechanisms underlying mtDNA removal during spermatogenesis, underscoring the pivotal role of this process in safeguarding maternal inheritance.
Project description:Expression analysis of cells the given amount of time after mtDNA was lost (or Nar1 expression was repressed) compared to pretreatment (or NAR1 being fully expressed). One time course experiment (Cells a given amount of time following mtDNA loss compared to cells with intact mtDNA), with 2 two condition experiments (Cells with the ATP1-111 genotype 27 hours following mtDNA loss compared to the same cells with intact mtDNA, and cells 27 hours following repression of NAR1 comared to cells expressing NAR1). Each data point had 3 biological replicates, and was dye-swapped. One replicate per array.
Project description:Individual variations in immune status and function determine responses to infection and contribute to disease severity and outcome. Patients exhibit considerable variation in clinical responses to infection with West Nile virus. We have undertaken a comprehensive characterization of the immune responses of a stratified cohort of patients with a history of West Nile virus infection to identify key mechanisms of resistance and susceptibility. We provide molecular profiles of cellular mechanisms of primary human immune cells defined through multifaceted interrogation including multiplexed gene expression analysis integrated with highly sensitive multidimensional flow cytometry. The availability of reliably curated patient cohorts and data-sharing and data mining techniques of high-throughout investigations should accelerate identification of critical elements of immune resistance to important pathogens