As sessile organisms,plants have evolved numerous strategies to acclimate to changes in environmental temperature.However,the molecular basis of this acclimation remains largely unclear.In this study we identified a t...As sessile organisms,plants have evolved numerous strategies to acclimate to changes in environmental temperature.However,the molecular basis of this acclimation remains largely unclear.In this study we identified a tRNAHis guanylyltransferase,AET1,which contributes to the modification of pre-tRNAH,s and is required for normal growth under high-temperature conditions in rice.Interestingly,AET1 possibly interacts with both RACK1A and elF3h in the endoplasmic reticulum.Notably,AET1 can directly bind to OsARF mRNAs including the uORFs of OsARF19 and OsARF23,indicating that AET1 is associated with translation regulation.Furthermore,polysome profiling assays suggest that the translational status remains unaffected in the aet1 mutant,but that the translational efficiency of OsARF19 and OsARF23 is reduced;moreover,OsARF23 protein levels are obviously decreased in the aet1 mutant under high temperature,implying that AET1 regulates auxin signaling in response to high temperature.Ourfindings provide new insights into the molecular mechanisms whereby AET1 regulates the environmental temperature response in rice by playing a dual role in tRNA modification and translational control.展开更多
Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactiv...Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactive transcription despite heavy translational requirements for continued growth and differentiation. Hence, spermatogenesis is highly reliant on mechanisms of posttranscriptional regulation of gene expression, facilitated by RNA binding proteins （RBPs）, which remain abundantly expressed throughout this process. One such group of proteins is the Musashi family, previously identified as critical regulators of testis germ cell development and meiosis in Drosophila, and also shown to be vital to sperm development and reproductive potential in the mouse. This review describes the role and function of RBPs our recent knowledge of the Musashi proteins in spermatogenesis. within the scope of male germ cell development, focusing on The functional mechanisms utilized by RBPs within the cell are outlined in depth, and the significance of sub-cellular localization and stage-specific expression in relation to the mode and impact of posttranscriptional regulation is also highlighted. We emphasize the historical role of the Musashi family of RBPs in stem cell function and cell fate determination, as originally characterized in Drosophila and Xenopus, and conclude with our current understanding of the differential roles and functions of the mammalian Musashi proteins, Musashi-1 and Musashi-2, with a primary focus on our findings in spermatogenesis. This review highlights both the essential contribution of RBPs to posttranscriptional regulation and the importance of the Musashi family as master regulators of male gamete development.展开更多
Heat shock response is a classical stress-induced regulatory system in bacteria, character- ized by extensive transcriptional reprogramming. To compare the impact of heat stress on the tran- scriptome and translatome ...Heat shock response is a classical stress-induced regulatory system in bacteria, character- ized by extensive transcriptional reprogramming. To compare the impact of heat stress on the tran- scriptome and translatome in Escherich＆ coli, we conducted ribosome profiling in parallel with RNA-Seq to investigate the alterations in transcription and translation efficiency when E. coli cells were exposed to a mild heat stress （from 30 ~C to 45 ~C）. While general changes in ribosome foot- prints correlate with the changes of mRNA transcripts upon heat stress, a number of genes show differential changes at the transcription and translation levels. Translation efficiency of a few genes that are related to environment stimulus response is up-regulated, and in contrast, some genes func- tioning in mRNA translation and amino acid biosynthesis are down-regulated at the translation level in response to heat stress. Moreover, our ribosome occupancy data suggest that in generalribosomes accumulate remarkably in the starting regions of ORFs upon heat stress. This study pro- vides additional insights into bacterial gene expression in response to heat stress, and suggests the presence of stress-induced but yet-to-be characterized cellular regulatory mechanisms of gene expression at translation level.展开更多
The metabolic enzyme isocitrate dehydrogenase 1(IDH1)catalyzes the oxidative decarboxylation of isocitrate to a-ketoglutarate(a-KG).Its mutation often leads to aberrant gene expression in cancer.IDH1 was reported to b...The metabolic enzyme isocitrate dehydrogenase 1(IDH1)catalyzes the oxidative decarboxylation of isocitrate to a-ketoglutarate(a-KG).Its mutation often leads to aberrant gene expression in cancer.IDH1 was reported to bind thousands of RNA transcripts in a sequence-dependent manner;yet,the functional significance of this RNA-binding activity remains elusive.Here,we report that IDH1 promotes mRNA translation via direct associations with polysome mRNA and translation machinery.Comprehensive proteomic analysis in embryonic stem cells(ESCs)revealed strikingenrichmentof ribosomal proteins and translation regulators in IDH1-bound protein interactomes.We performed ribosomal profiling and analyzed mRNA transcripts that are associated with actively translating polysomes.Interestingly,knockout of IDH1 in ESCs led to significant downregulation of polysome-bound mRNA in IDH1 targets and subtle upregulation of ribosome densities at the start codon,indicating inefficient translation initiation upon loss of IDH1.Tethering IDH1 to a luciferase mRNA via the MS2-MBP system promotes luciferase translation,independently of the catalytic activity of IDH1.Intriguingly,IDH1 fails to enhance luciferase translation driven by an internal ribosome entry site.Together,these results reveal an unforeseen role of IDH1 in fine-tuning cap-dependent translation via the initiation step.展开更多
Thymidylate synthase (TS;TYMS) is a pivotal enzyme in the DNA synthesis pathway. The 5’UTR of TYMS gene has a polymorphic 28 bp segment. Presence of two or three repeats of this unique 28 bp sequence is common. A dis...Thymidylate synthase (TS;TYMS) is a pivotal enzyme in the DNA synthesis pathway. The 5’UTR of TYMS gene has a polymorphic 28 bp segment. Presence of two or three repeats of this unique 28 bp sequence is common. A distinct population distribution pattern for this polymorphic trait among different racial groups had been reported. We analyzed TYMS genotype in the peripheral blood mononucleocytes (PBMC) of 74 individuals in the South Florida region of the United States of America. The number of 28 bp repeats in the 5’ UTR was determined by PCR followed by agarose gel electrophoresis. The distribution of the three different genotypes was found to be 35.1% for 2R/2R, 39.2% for 2R/3R and 24.3% for 3R/3R. One individual was detected with 3R/4R genotype. Functional analyses associated homozygous for three repeats (3R/3R) to higher TYMS expression and therefore poor prognosis to chemotherapy. The other possible genotypes viz 2R/2R or 2R/3R is proposed to have better prognosis. However, there are reports that challenge this observation.展开更多
基金supported by the grants from National Natural Science Foundation of China (31630052,31788103)the Ministry of Science and Technology of China (2016YFD0100902,2016YFD0100604)+2 种基金Chinese Academy of Sciences (QYZDY-SSW-SMC023,XDB27010104)the Shanghai Science and Technology Development (18JC1415000)CASCroucher Funding Scheme for Joint Laboratories,and National Key Laboratory of Plant Molecular Genetics,China.
文摘As sessile organisms,plants have evolved numerous strategies to acclimate to changes in environmental temperature.However,the molecular basis of this acclimation remains largely unclear.In this study we identified a tRNAHis guanylyltransferase,AET1,which contributes to the modification of pre-tRNAH,s and is required for normal growth under high-temperature conditions in rice.Interestingly,AET1 possibly interacts with both RACK1A and elF3h in the endoplasmic reticulum.Notably,AET1 can directly bind to OsARF mRNAs including the uORFs of OsARF19 and OsARF23,indicating that AET1 is associated with translation regulation.Furthermore,polysome profiling assays suggest that the translational status remains unaffected in the aet1 mutant,but that the translational efficiency of OsARF19 and OsARF23 is reduced;moreover,OsARF23 protein levels are obviously decreased in the aet1 mutant under high temperature,implying that AET1 regulates auxin signaling in response to high temperature.Ourfindings provide new insights into the molecular mechanisms whereby AET1 regulates the environmental temperature response in rice by playing a dual role in tRNA modification and translational control.
文摘Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactive transcription despite heavy translational requirements for continued growth and differentiation. Hence, spermatogenesis is highly reliant on mechanisms of posttranscriptional regulation of gene expression, facilitated by RNA binding proteins （RBPs）, which remain abundantly expressed throughout this process. One such group of proteins is the Musashi family, previously identified as critical regulators of testis germ cell development and meiosis in Drosophila, and also shown to be vital to sperm development and reproductive potential in the mouse. This review describes the role and function of RBPs our recent knowledge of the Musashi proteins in spermatogenesis. within the scope of male germ cell development, focusing on The functional mechanisms utilized by RBPs within the cell are outlined in depth, and the significance of sub-cellular localization and stage-specific expression in relation to the mode and impact of posttranscriptional regulation is also highlighted. We emphasize the historical role of the Musashi family of RBPs in stem cell function and cell fate determination, as originally characterized in Drosophila and Xenopus, and conclude with our current understanding of the differential roles and functions of the mammalian Musashi proteins, Musashi-1 and Musashi-2, with a primary focus on our findings in spermatogenesis. This review highlights both the essential contribution of RBPs to posttranscriptional regulation and the importance of the Musashi family as master regulators of male gamete development.
基金supported by the National Natural Science Foundation of China(Grant Nos.31630087,31422016,and 31470722 to NGGrant Nos.31671381 and 91540109 to XY)
文摘Heat shock response is a classical stress-induced regulatory system in bacteria, character- ized by extensive transcriptional reprogramming. To compare the impact of heat stress on the tran- scriptome and translatome in Escherich＆ coli, we conducted ribosome profiling in parallel with RNA-Seq to investigate the alterations in transcription and translation efficiency when E. coli cells were exposed to a mild heat stress （from 30 ~C to 45 ~C）. While general changes in ribosome foot- prints correlate with the changes of mRNA transcripts upon heat stress, a number of genes show differential changes at the transcription and translation levels. Translation efficiency of a few genes that are related to environment stimulus response is up-regulated, and in contrast, some genes func- tioning in mRNA translation and amino acid biosynthesis are down-regulated at the translation level in response to heat stress. Moreover, our ribosome occupancy data suggest that in generalribosomes accumulate remarkably in the starting regions of ORFs upon heat stress. This study pro- vides additional insights into bacterial gene expression in response to heat stress, and suggests the presence of stress-induced but yet-to-be characterized cellular regulatory mechanisms of gene expression at translation level.
基金This work was supported in part by the National Natural Science Foundation of China(31471219 and 31630095)the National Basic Research Program of China(2017YFA0504204)the Center for Life Sciences at Tsinghua University.
文摘The metabolic enzyme isocitrate dehydrogenase 1(IDH1)catalyzes the oxidative decarboxylation of isocitrate to a-ketoglutarate(a-KG).Its mutation often leads to aberrant gene expression in cancer.IDH1 was reported to bind thousands of RNA transcripts in a sequence-dependent manner;yet,the functional significance of this RNA-binding activity remains elusive.Here,we report that IDH1 promotes mRNA translation via direct associations with polysome mRNA and translation machinery.Comprehensive proteomic analysis in embryonic stem cells(ESCs)revealed strikingenrichmentof ribosomal proteins and translation regulators in IDH1-bound protein interactomes.We performed ribosomal profiling and analyzed mRNA transcripts that are associated with actively translating polysomes.Interestingly,knockout of IDH1 in ESCs led to significant downregulation of polysome-bound mRNA in IDH1 targets and subtle upregulation of ribosome densities at the start codon,indicating inefficient translation initiation upon loss of IDH1.Tethering IDH1 to a luciferase mRNA via the MS2-MBP system promotes luciferase translation,independently of the catalytic activity of IDH1.Intriguingly,IDH1 fails to enhance luciferase translation driven by an internal ribosome entry site.Together,these results reveal an unforeseen role of IDH1 in fine-tuning cap-dependent translation via the initiation step.
文摘Thymidylate synthase (TS;TYMS) is a pivotal enzyme in the DNA synthesis pathway. The 5’UTR of TYMS gene has a polymorphic 28 bp segment. Presence of two or three repeats of this unique 28 bp sequence is common. A distinct population distribution pattern for this polymorphic trait among different racial groups had been reported. We analyzed TYMS genotype in the peripheral blood mononucleocytes (PBMC) of 74 individuals in the South Florida region of the United States of America. The number of 28 bp repeats in the 5’ UTR was determined by PCR followed by agarose gel electrophoresis. The distribution of the three different genotypes was found to be 35.1% for 2R/2R, 39.2% for 2R/3R and 24.3% for 3R/3R. One individual was detected with 3R/4R genotype. Functional analyses associated homozygous for three repeats (3R/3R) to higher TYMS expression and therefore poor prognosis to chemotherapy. The other possible genotypes viz 2R/2R or 2R/3R is proposed to have better prognosis. However, there are reports that challenge this observation.
