RNA polymerase transcriptional pausing represents a major checkpoint in transcription in bacteria and metazoans,but it is unknown whether this phenomenon occurs in plant organelles.Here,we report that transcriptional ...RNA polymerase transcriptional pausing represents a major checkpoint in transcription in bacteria and metazoans,but it is unknown whether this phenomenon occurs in plant organelles.Here,we report that transcriptional pausing occurs in chloroplasts.We found that mTERF5 specifically and positively regulates the transcription of chloroplast psbEFLJ in Arabidopsis thaliana that encodes four key subunits of photosystem II.We found that mTERF5 causes the plastid-encoded RNA polymerase(PEP)complex to pause at psbEFLJ by binding to the+30 to+51 region of double-stranded DNA.Moreover,we revealed that mTERF5 interacts with pTAC6,an essential subunit of the PEP complex,although pTAC6 is not involved in the transcriptional pausing at psbEFLJ.We showed that mTERF5 recruits additional pTAC6 to the transcriptionally paused region of psbEFLJ,and the recruited pTAC6 proteins could be assembled into the PEP complex to regulate psbEFLJ transcription.Taken together,our findings shed light on the role of transcriptional pausing in chloroplast transcription in plants.展开更多
Lesions on the DNA template can impact transcription via distinct regulatory pathways.Ionizing radiation(IR)as the mainstay modality for many malignancies elicits most of the cytotoxicity by inducing a variety of DNA ...Lesions on the DNA template can impact transcription via distinct regulatory pathways.Ionizing radiation(IR)as the mainstay modality for many malignancies elicits most of the cytotoxicity by inducing a variety of DNA damages in the genome.How the IR treatment alters the transcription cycle and whether it contributes to the development of radioresistance remain poorly understood.Here,we report an increase in the paused RNA polymerase II(RNAPII),as indicated by the phosphorylation at serine 5 residue of its C-terminal domain,in recurrent nasopharyngeal carcinoma(NPC)patient samples after IR treatment and cultured NPC cells developing IR resistance.Reducing the pool of paused RNAPII by either inhibiting TFIIH-associated CDK7 or stimulating the positive transcription elongation factor b,a CDK9-CycT1 heterodimer,attenuates IR resistance of NPC cells.Interestingly,the poly(ADP-ribosyl)ation of CycT1,which disrupts its phase separation,is elevated in the IR-resistant cells.Mutation of the major poly(ADP-ribosyl)ation sites of CycT1 decreases RNAPII pausing and restores IR sensitivity.Genome-wide chromatin immunoprecipitation followed by sequencing analyses reveal that several genes involved in radiation response and cell cycle control are subject to the regulation imposed by the paused RNAPII.Particularly,we identify the NIMA-related kinase NEK7 under such regulation as a new radioresistancefactor,whose downregulation results in the increased chromosome instability,enabling the development of IR resistance.Overall,our results highlight a novel link between the alteration in the transcription cycle and the acquisition of IR resistance,opening up new opportunities to increase the efficacy of radiotherapy and thwart radioresistance in NpC.展开更多
Transcription termination of nearly all protein-coding genes in mammals requires 3’end processing by a multiprotein complex that will cleave and polyadenylate the messenger RNA precursor.Because a variety of enzyme c...Transcription termination of nearly all protein-coding genes in mammals requires 3’end processing by a multiprotein complex that will cleave and polyadenylate the messenger RNA precursor.Because a variety of enzyme complexes intervene,3’end processing was thought to be fundamentally complex and subject to a multitude of regulatory effects.The possibility to select just one out of several polyadenylation sites,in particular,has caused much questioning and speculation.What appear to be separate mechanisms however can be combined into a defined set of rules,allowing for a relatively simple interpretation of 3’end processing.Ultimately,readiness of the terminal exon splice site determines when a transcript reaches the maturity to select a nearby polyadenylation signal.Transcriptional pausing then acts in concert,extending the timeframe during which the transcription complex is close to polyadenylation sites.Since RNA polymerase pausing is governed by the same type of sequences in bacteria and metazoans,mammalian transcription termination resembles its prokaryote counterpart more than generally thought.展开更多
Brown adipose tissue(BAT)plays a key role in thermogenesis during acute cold exposure.However,it remains unclear how BAT is prepared to rapidly turn on thermogenic genes.Here,we show that damage-specific DNA binding p...Brown adipose tissue(BAT)plays a key role in thermogenesis during acute cold exposure.However,it remains unclear how BAT is prepared to rapidly turn on thermogenic genes.Here,we show that damage-specific DNA binding protein 1(DDB1)mediates the rapid transcription of thermogenic genes upon acute cold exposure.Adipose-or BAT-specific Ddb1 knockout mice show severely whitened BAT and significantly decreased expression of thermogenic genes.These mice develop hypothermia when subjected to acute cold exposure at 4℃ and partial lipodystrophy on a high-fat diet due to deficiency in fatty acid oxidation.Mechanistically,DDB1 binds the promoters of Ucp1 and Ppargc1a and recruits positive transcriptional elongation factor b(P-TEFb)to release promoter-proximally paused RNA polymerase II(Pol II),thereby enabling rapid and synchronized transcription of thermogenic genes upon acute cold exposure.Our findings have thus provided a regulatory mechanism of how BAT is prepared to respond to acute cold challenge.展开更多
基金the National Natural Science Foundation of China(reference number 31730102)the State Key Basic Research and Development Plan of China(reference number 2015CB150105)+2 种基金the Key Research Plan of Frontier Sciences of the Chinese Academy of Sciences(reference number QYZDJ-SSW-SMC003)the Strategic Priority Research Program of the Chinese Academy of Sciences(reference number XDB17030100)the National Key Scientific Instrument and Equipment Development Project of China(grant no.2013YQ030595).
文摘RNA polymerase transcriptional pausing represents a major checkpoint in transcription in bacteria and metazoans,but it is unknown whether this phenomenon occurs in plant organelles.Here,we report that transcriptional pausing occurs in chloroplasts.We found that mTERF5 specifically and positively regulates the transcription of chloroplast psbEFLJ in Arabidopsis thaliana that encodes four key subunits of photosystem II.We found that mTERF5 causes the plastid-encoded RNA polymerase(PEP)complex to pause at psbEFLJ by binding to the+30 to+51 region of double-stranded DNA.Moreover,we revealed that mTERF5 interacts with pTAC6,an essential subunit of the PEP complex,although pTAC6 is not involved in the transcriptional pausing at psbEFLJ.We showed that mTERF5 recruits additional pTAC6 to the transcriptionally paused region of psbEFLJ,and the recruited pTAC6 proteins could be assembled into the PEP complex to regulate psbEFLJ transcription.Taken together,our findings shed light on the role of transcriptional pausing in chloroplast transcription in plants.
基金This project has been supported by grants from the National Natural ScienceFoundation of China(32170821 and 92153301 to K.Y.and 32101034 to F.C.)the Ministry of Science and Technologyyof the People's Republic of China(2021YFC2701202)+2 种基金Department of Science&Technology of Hunan Province(2021J10054 and 2019SK1012 to K.Y.,2021J41049 to C.Y.,and the Innovative Team Program 2019RS1010)Central South University(the Innovationdriven Team Project 2020CX016)K.Y.is supported by the National Thousand Talents Program for Young Outstanding Scientists.
文摘Lesions on the DNA template can impact transcription via distinct regulatory pathways.Ionizing radiation(IR)as the mainstay modality for many malignancies elicits most of the cytotoxicity by inducing a variety of DNA damages in the genome.How the IR treatment alters the transcription cycle and whether it contributes to the development of radioresistance remain poorly understood.Here,we report an increase in the paused RNA polymerase II(RNAPII),as indicated by the phosphorylation at serine 5 residue of its C-terminal domain,in recurrent nasopharyngeal carcinoma(NPC)patient samples after IR treatment and cultured NPC cells developing IR resistance.Reducing the pool of paused RNAPII by either inhibiting TFIIH-associated CDK7 or stimulating the positive transcription elongation factor b,a CDK9-CycT1 heterodimer,attenuates IR resistance of NPC cells.Interestingly,the poly(ADP-ribosyl)ation of CycT1,which disrupts its phase separation,is elevated in the IR-resistant cells.Mutation of the major poly(ADP-ribosyl)ation sites of CycT1 decreases RNAPII pausing and restores IR sensitivity.Genome-wide chromatin immunoprecipitation followed by sequencing analyses reveal that several genes involved in radiation response and cell cycle control are subject to the regulation imposed by the paused RNAPII.Particularly,we identify the NIMA-related kinase NEK7 under such regulation as a new radioresistancefactor,whose downregulation results in the increased chromosome instability,enabling the development of IR resistance.Overall,our results highlight a novel link between the alteration in the transcription cycle and the acquisition of IR resistance,opening up new opportunities to increase the efficacy of radiotherapy and thwart radioresistance in NpC.
基金The author is financed in part by the Spanish Government(Ministerio de Ciencia e Innovación,Grant MCIN/AEI PID2019-110574RB-I00).
文摘Transcription termination of nearly all protein-coding genes in mammals requires 3’end processing by a multiprotein complex that will cleave and polyadenylate the messenger RNA precursor.Because a variety of enzyme complexes intervene,3’end processing was thought to be fundamentally complex and subject to a multitude of regulatory effects.The possibility to select just one out of several polyadenylation sites,in particular,has caused much questioning and speculation.What appear to be separate mechanisms however can be combined into a defined set of rules,allowing for a relatively simple interpretation of 3’end processing.Ultimately,readiness of the terminal exon splice site determines when a transcript reaches the maturity to select a nearby polyadenylation signal.Transcriptional pausing then acts in concert,extending the timeframe during which the transcription complex is close to polyadenylation sites.Since RNA polymerase pausing is governed by the same type of sequences in bacteria and metazoans,mammalian transcription termination resembles its prokaryote counterpart more than generally thought.
基金This work was supported by the National Key R&D Program of China(2020YFA0803601)the National Natural Science Foundation of China(32125022 and 32101046)the China Postdoctoral Science Foundation(2019M661348 and 2020T130115).
文摘Brown adipose tissue(BAT)plays a key role in thermogenesis during acute cold exposure.However,it remains unclear how BAT is prepared to rapidly turn on thermogenic genes.Here,we show that damage-specific DNA binding protein 1(DDB1)mediates the rapid transcription of thermogenic genes upon acute cold exposure.Adipose-or BAT-specific Ddb1 knockout mice show severely whitened BAT and significantly decreased expression of thermogenic genes.These mice develop hypothermia when subjected to acute cold exposure at 4℃ and partial lipodystrophy on a high-fat diet due to deficiency in fatty acid oxidation.Mechanistically,DDB1 binds the promoters of Ucp1 and Ppargc1a and recruits positive transcriptional elongation factor b(P-TEFb)to release promoter-proximally paused RNA polymerase II(Pol II),thereby enabling rapid and synchronized transcription of thermogenic genes upon acute cold exposure.Our findings have thus provided a regulatory mechanism of how BAT is prepared to respond to acute cold challenge.
