Project description:Plants have evolved sophisticated mechanisms to regulate gene expression to activate immune responses against pathogen infections. However, how the translation system contributes to plant immunity is largely unknown. The evolutionarily conserved thiolation modification of tRNA ensures efficient decoding during translation. Here we show that tRNA thiolation is required for plant immunity in Arabidopsis. The Arabidopsis cgb mutant is hyper-susceptible to the pathogen Pseudomonas syringae. CGB encodes ROL5, a homolog of yeast NCS6 required for tRNA thiolation. ROL5 physically interacts with CTU2, a homolog of yeast NCS2. Mutations in either ROL5 or CTU2 result in loss of tRNA thiolation. Further analyses reveal that tRNA thiolation is required for both transcriptional reprogramming and translational reprogramming during immune responses. The translation efficiency of immune-related proteins reduces when tRNA thiolation is absent. Our study not only uncovers a new biological function of tRNA thiolation but also reveals a new mechanism for plant immunity.
Project description:Plants have evolved sophisticated mechanisms to regulate gene expression to activate immune responses against pathogen infections. However, how the translation system contributes to plant immunity is largely unknown. The evolutionarily conserved thiolation modification of tRNA ensures efficient decoding during translation. Here we show that tRNA thiolation is required for plant immunity in Arabidopsis. The Arabidopsis cgb mutant is hyper-susceptible to the pathogen Pseudomonas syringae. CGB encodes ROL5, a homolog of yeast NCS6 required for tRNA thiolation. ROL5 physically interacts with CTU2, a homolog of yeast NCS2. Mutations in either ROL5 or CTU2 result in loss of tRNA thiolation. Further analyses reveal that tRNA thiolation is required for both transcriptional reprogramming and translational reprogramming during immune responses. The translation efficiency of immune-related proteins reduces when tRNA thiolation is absent. Our study not only uncovers a new biological function of tRNA thiolation but also reveals a new mechanism for plant immunity.
Project description:Post-transcriptional modifications are important for transfer RNAs (tRNAs) to be efficient and accurate in translation on the ribosome. The m1G37 modification on a subset of tRNAs in bacteria are generated by a conserved methyltransferase TrmD and is essential for bacterial growth. Previous studies showed that m1G37 has an important role in preventing translational frameshifting and also that this modification is coupled with aminoacylation of tRNAs for proline. Here we performed suppressor screening to isolate a mutant E. coli cell that lacks TrmD but is viable, and the whole-genome sequencing revealed several mutations on prolyl-tRNA synthetase (ProRS) gene conferring cell viability in the absence of TrmD. Biochemical assays confirmed uncoupling of m1G37 modification and aminoacylation, and cell-based assays uncovered the critical role of m1G37 in supporting Wobble decoding.
Project description:N7-methylguanosine (m7G) in variable loop region of tRNA stabilizes target tRNA expression, which is catalyzed by METTL1/WDR4 heterodimer. Here, we unveil essential functions of Mettl1 in Drosophila fertility. Mettl1-knockout (Mettl1-KO) decreases elongated spermatid and mature sperm, which is fully rescued by Mettl1-transgene expression, but not catalytic dead Mettl1-transgene, demonstrating that Mettl1-dependent m7G is required for spermatogenesis. Mettl1-KO shows loss of m7G modification on subset of tRNAs and decreased level of tRNA expression. Strikingly, overexpression of translational elongation factor EF1α that can compete with rapid tRNA decay (RTD) pathway in S. cerevisiae, significantly counteract the sterility in Mettl1-KO male, supporting a critical role of m7G tRNA modification in spermatogenesis. Ribo-seq analysis shows that Mettl1-KO elevates ribosome collisions at codons decoded by reduced tRNAs and significantly reduces translation of genes involved in elongated spermatid formation and sperm stability. These findings reveal a developmental role for m7G tRNA modifications and suggest that m7G modification-dependent tRNA stability differs among tissues.
Project description:The tRNA N7-methylguanosine (m7G) modification is not essential for yeast growth, but in mammals mis-regulations of tRNA m7G modification cause stem cell defect and developmental disorders. Here we found that homozygous mutated WDR4 caused microcephaly, retardation in motor coordination and spatial learning ability in mice, which mimics the symptom in human patients with WDR4 mutation. Further analysis revealed that homozygous mutation of WDR4 impaired tRNA m7G modification and reduced the translation level of genes involved in mTOR signaling pathway in mouse brain, which further caused endoplasmic reticulum (ER) stress and cell death. Our study uncovered a new layer of translation regulation mechanism mediated by tRNA m7G modification, provided strong evidence to support the important physiological function of mis-regulated tRNA modification in neuron disorders.
Project description:The tRNA N7-methylguanosine (m7G) modification is not essential for yeast growth, but in mammals mis-regulations of tRNA m7G modification cause stem cell defect and developmental disorders. Here we found that homozygous mutated WDR4 caused microcephaly, retardation in motor coordination and spatial learning ability in mice, which mimics the symptom in human patients with WDR4 mutation. Further analysis revealed that homozygous mutation of WDR4 impaired tRNA m7G modification and reduced the translation level of genes involved in mTOR signaling pathway in mouse brain, which further caused endoplasmic reticulum (ER) stress and cell death. Our study uncovered a new layer of translation regulation mechanism mediated by tRNA m7G modification, provided strong evidence to support the important physiological function of mis-regulated tRNA modification in neuron disorders.
Project description:The tRNA N7-methylguanosine (m7G) modification is not essential for yeast growth, but in mammals mis-regulations of tRNA m7G modification cause stem cell defect and developmental disorders. Here we found that homozygous mutated WDR4 caused microcephaly, retardation in motor coordination and spatial learning ability in mice, which mimics the symptom in human patients with WDR4 mutation. Further analysis revealed that homozygous mutation of WDR4 impaired tRNA m7G modification and reduced the translation level of genes involved in mTOR signaling pathway in mouse brain, which further caused endoplasmic reticulum (ER) stress and cell death. Our study uncovered a new layer of translation regulation mechanism mediated by tRNA m7G modification, provided strong evidence to support the important physiological function of mis-regulated tRNA modification in neuron disorders.
Project description:The tRNA N7-methylguanosine (m7G) modification is not essential for yeast growth, but in mammals mis-regulations of tRNA m7G modification cause stem cell defect and developmental disorders. Here we found that homozygous mutated WDR4 caused microcephaly, retardation in motor coordination and spatial learning ability in mice, which mimics the symptom in human patients with WDR4 mutation. Further analysis revealed that homozygous mutation of WDR4 impaired tRNA m7G modification and reduced the translation level of genes involved in mTOR signaling pathway in mouse brain, which further caused endoplasmic reticulum (ER) stress and cell death. Our study uncovered a new layer of translation regulation mechanism mediated by tRNA m7G modification, provided strong evidence to support the important physiological function of mis-regulated tRNA modification in neuron disorders.
2024-10-16 | GSE229240 | GEO
Project description:The thiolation modification of tRNA is essential for plant immunity