SPELL - Nematode

Citation	Lin YF, Schulz AM, Pellegrino MW, Lu Y, Shaham S, Haynes CM. Maintenance and propagation of a deleterious mitochondrial genome by the mitochondrial unfolded protein response. Nature, 2016.
PubMed ID	27135930
Short Description	Maintenance and propagation of a deleterious mitochondrial genome by the mitochondrial unfolded protein response. GEO Record: GSE73669 Platform: GPL200 Download gene-centric, log2 transformed data: WBPaper00049538.ce.mr.csv
# of Conditions	6
Full Description	Mitochondrial genomes (mitochondrial DNA, mtDNA) encode essential oxidative phosphorylation (OXPHOS) components. Because hundreds of mtDNAs exist per cell, a deletion in a single mtDNA has little impact. However, if the deletion genome is enriched, OXPHOS declines, resulting in cellular dysfunction. For example, Kearns-Sayre syndrome is caused by a single heteroplasmic mtDNA deletion. More broadly, mtDNA deletion accumulation has been observed in individual muscle cells and dopaminergic neurons during ageing. It is unclear how mtDNA deletions are tolerated or how they are propagated in somatic cells. One mechanism by which cells respond to OXPHOS dysfunction is by activating the mitochondrial unfolded protein response (UPR(mt)), a transcriptional response mediated by the transcription factor ATFS-1 that promotes the recovery and regeneration of defective mitochondria. Here we investigate the role of ATFS-1 in the maintenance and propagation of a deleterious mtDNA in a heteroplasmic Caenorhabditis elegans strain that stably expresses wild-type mtDNA and mtDNA with a 3.1-kilobase deletion (mtDNA) lacking four essential genes. The heteroplasmic strain, which has 60% mtDNA, displays modest mitochondrial dysfunction and constitutive UPR(mt) activation. ATFS-1 impairment reduced the mtDNA nearly tenfold, decreasing the total percentage to 7%. We propose that in the context of mtDNA heteroplasmy, UPR(mt) activation caused by OXPHOS defects propagates or maintains the deleterious mtDNA in an attempt to recover OXPHOS activity by promoting mitochondrial biogenesis and dynamics. Experimental Details: WBPaper00049538:N2_rep1 WBPaper00049538:atfs-1(et18)_rep1 WBPaper00049538:N2_rep2 WBPaper00049538:atfs-1(et18)_rep2 WBPaper00049538:N2_rep3 WBPaper00049538:atfs-1(et18)_rep3.
Tags	Method: microarray, Species: Caenorhabditis elegans, Topic: response to unfolded protein