Mammalian mitochondria have small genomes encoding very limited numbers of proteins.Over one thousand proteins and noncoding RNAs encoded by the nuclear genome must be imported from the cytosol into the mitochondria.H...Mammalian mitochondria have small genomes encoding very limited numbers of proteins.Over one thousand proteins and noncoding RNAs encoded by the nuclear genome must be imported from the cytosol into the mitochondria.Here,we report the identification of hundreds of circular RNAs(mecciRNAs)encoded by the mitochondrial genome.We provide both in vitro and in vivo evidence to show that mecciRNAs facilitate the mitochondrial entry of nuclear-encoded proteins by serving as molecular chaperones in the folding of imported proteins.Known components involved in mitochondrial protein and RNA importation,such as TOM40 and PNPASE,interact with mecciRNAs and regulate protein entry.The expression of mecciRNAs is regulated,and these transcripts are critical for the adaption of mitochondria to physiological conditions and diseases such as stresses and cancers by modulating mitochondrial protein importation.mecciRNAs and their associated physiological roles add categories and functions to the known eukaryotic circular RNAs and shed novel light on the communication between mitochondria and the nucleus.展开更多
Summary of main observation and conclusion Owing to the easy functionalization of 3-haloindolines to many biologically active compounds,extensive efforts have been made for their efficient preparation.Herein,an electr...Summary of main observation and conclusion Owing to the easy functionalization of 3-haloindolines to many biologically active compounds,extensive efforts have been made for their efficient preparation.Herein,an electrochemical dearomative bromo-and chloro-cyclization of tryptamine and tryp-tophol derivatives has been developed under undivided electrolytic conditions.In this protocol,neither external chemical oxidants nor harsh conditions are needed,and a wide range of substituted hexahydropyrroloindolines/tetrahydrofuroindolines are obtained with halide ion in high efficiencies.Moreo-ver,this electrolysis could also be scaled up to gram synthesis with good yields.展开更多
Medium-sized nitrogen heterocycles are prevalent motifs in many kinds of bioactive molecules and natural products.Owing to the unfavorable enthalpic and entropic barriers during the transition states,access to medium-...Medium-sized nitrogen heterocycles are prevalent motifs in many kinds of bioactive molecules and natural products.Owing to the unfavorable enthalpic and entropic barriers during the transition states,access to medium-sized rings is challenging.Herein,a general and practical electrochemical ringexpansion protocol has been developed from commercially available benzocyclic ketones and amides.In this regard,a series of highly functionalized eightto eleven-membered lactams could be successfully accessed in high yields and efficiencies.展开更多
基金Supported by grants to G. S.: the National Key R&D Program of China (2019YFA0802600 and 2018YFC1004500)the National Natural Science Foundation of China (31725016, 31930019, and 91940303)and the Strategic Priority Research Program (Pilot Study) “Biological basis of aging and therapeutic strategies” of the Chinese Academy of Sciences (XDPB10).
文摘Mammalian mitochondria have small genomes encoding very limited numbers of proteins.Over one thousand proteins and noncoding RNAs encoded by the nuclear genome must be imported from the cytosol into the mitochondria.Here,we report the identification of hundreds of circular RNAs(mecciRNAs)encoded by the mitochondrial genome.We provide both in vitro and in vivo evidence to show that mecciRNAs facilitate the mitochondrial entry of nuclear-encoded proteins by serving as molecular chaperones in the folding of imported proteins.Known components involved in mitochondrial protein and RNA importation,such as TOM40 and PNPASE,interact with mecciRNAs and regulate protein entry.The expression of mecciRNAs is regulated,and these transcripts are critical for the adaption of mitochondria to physiological conditions and diseases such as stresses and cancers by modulating mitochondrial protein importation.mecciRNAs and their associated physiological roles add categories and functions to the known eukaryotic circular RNAs and shed novel light on the communication between mitochondria and the nucleus.
基金This work was supported by the National Natural Science Foundation of China(No.21520102003)the Hubei Province Natural Science Foundation of China(No,2017CFA010)The Pro-gram of Introducing Talents of Discipline to Universities of China(111 Program)is also appreciated.
文摘Summary of main observation and conclusion Owing to the easy functionalization of 3-haloindolines to many biologically active compounds,extensive efforts have been made for their efficient preparation.Herein,an electrochemical dearomative bromo-and chloro-cyclization of tryptamine and tryp-tophol derivatives has been developed under undivided electrolytic conditions.In this protocol,neither external chemical oxidants nor harsh conditions are needed,and a wide range of substituted hexahydropyrroloindolines/tetrahydrofuroindolines are obtained with halide ion in high efficiencies.Moreo-ver,this electrolysis could also be scaled up to gram synthesis with good yields.
基金the National Natural Science Foundation of China(no.21520102003)the Hubei Province Natural Science Foundation of China(no.2017CFA010)the Program of Introducing Talents of Discipline to Universities of China(111 Program)for their generous financial support.
文摘Medium-sized nitrogen heterocycles are prevalent motifs in many kinds of bioactive molecules and natural products.Owing to the unfavorable enthalpic and entropic barriers during the transition states,access to medium-sized rings is challenging.Herein,a general and practical electrochemical ringexpansion protocol has been developed from commercially available benzocyclic ketones and amides.In this regard,a series of highly functionalized eightto eleven-membered lactams could be successfully accessed in high yields and efficiencies.
