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Effects of ccf-1 RNAi on C. elegans response to cadmium and acrylamide

ABSTRACT: In a genome-wide RNAi screen to identify activators of numr-1, a cadmium responsive gene involved in RNA splicing regulation, we isolated ccf-1 as a gene that is required for cadmium-induced numr-1 activation. The ccf-1 gene encodes a deadenylase within the CCR4-NOT complex that generally serves to suppress gene expression by initiating mRNA degradation. However, a role for ccf-1 as a positive regulator of stress-induced gene expression remains to be characterized. Silencing of ccf-1 inhibits various classes of cadmium-inducible genes including several glutathione-s-transferase (gst) and heat shock protein genes. RNAi knockdown of ccf-1 significantly reduces lifespan and decreases survival in cadmium, implicating a role for ccf-1 in aging and stress protection. The ccf-1 gene is also required for resistance against acrylamide with RNAi depletion of ccf-1 inhibiting acrylamide-induced gst induction, decreasing survival in acrylamide stress, and increasing C. elegans sensitivity to acrylamide-induced neurodegeneration. Using RNA-sequencing, we observed that ccf-1 regulates ~28-35% of all genes induced by cadmium (500 out of 1802 DEG) or acrylamide (296 out of 851 DEG) by >2-fold. Clustering analysis of ccf-1 dependent cadmium or acrylamide up-regulated genes indicate significant enrichment to glutathione and cytochrome P450 metabolism, suggesting a central role for ccf-1 in regulating antioxidant defense across different stressors. Using a CCF-1::GFP translational reporter, we find that CCF-1 is broadly expressed in the intestine, muscle, and hypodemis. Interestingly, CCF-1::GFP strongly localizes to the intestinal nuclei, implicating a potential nuclear role for CCF-1 in transcriptional regulation that is distinct for its deadenylase function in the cytoplasm

ORGANISM(S): Caenorhabditis elegans

PROVIDER: GSE194057 | GEO | 2023/02/17

REPOSITORIES: GEO

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Project description:The glutathione S-transferase (GST) gene family codes for enzymes that detoxify xenobiotics by catalyzing the conjugation of xenobiotics to glutathione. Based on reports that inherited copy number variations (CNV) in the genome modulate some GST expression levels and with the knowledge that cigarette smoke contains >3000 xenobiotics, and that the small airway epithelium and alveolar macrophages are involved early in the pathogensis of smoking-induced lung disease, we asked: do germline CNVs modulate GST expression level in the small airway epithelium and alveolar macrophages? Affymetrix HG U133 Plus 2.0 microarrays were used to survey GST gene expression in the small airway epithelium and alveolar macrophages obtained by bronchoscopic brushings from current smokers (n=35) and nonsmokers (n=35). The CNV genotypes of these 70 subjects were determined by Affymetrix Human SNP array 5.0 chips. Sixteen % of subjects had deletions of both GSTM1 alleles. These deletions were associated with reduced GSTM1 mRNA levels in both the small airway epithelium (p<10-7) and alveolar macrophages (p<0.05). Thirty % of subjects had homozygous deletions of GSTT1 with concomitant reduced mRNA levels in both small airway epithelium and alveolar macrophages (p<10-7). In contrast, genes flanking the CNV regions of both GST genes showed no difference in expression level among subjects with and without the GST deletions (p>0.3). Interestingly, GSTT2B, a duplicate gene of GSTT2, exhibited homozygous deletion in blood in 27% of subjects and was not expressed in small airway epithelium in the remainder of subjects but was expressed in alveolar macrophages of heterozygotes and wild type subjects, proportionate to genotype (p<10-3). These data demonstrate that highly prevalent CNV deletions of genes critical to ameliorating smoking-associated xenobiotic-induced damage in the lung can result in significant modulation of the gene expression levels, with the linear relationship of genotype to expression level suggesting minimal compensation of gene expression levels in heterozygotes consistent with GST polymorphisms playing a role in the risk for development of smoking-induced lung disease.

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Effects of ccf-1 RNAi on C. elegans response to cadmium and acrylamide

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