Based on the successful simulation of a typical winter urban boundary layer(UBL) process over Beijing area during the Beijing City Air Pollution Experiment (BECAPEX) in 2001by the use of MM5 coupled with urban canopy ...Based on the successful simulation of a typical winter urban boundary layer(UBL) process over Beijing area during the Beijing City Air Pollution Experiment (BECAPEX) in 2001by the use of MM5 coupled with urban canopy parameterization, a series of simulation experiments areperformed to investigate the effects of urban influence, surrounding terrain, and different extentof urbanization on urban boundary layer structures over Beijing area. The results of factorseparation experiments of urban influence indicate that the total effect of urban influence, whichis the synthetic effect of urban infrastructure on thermal and dynamic structures of atmosphere, isresponsible for the formation of main UBL features over Beijing area. Meanwhile, the relativeimportance of thermal and mechanical factors of urban infrastructure and interaction between thermaland mechanical factors for the formation and evolution of UBL over the Beijing area are alsoexplored. The results show that, during nighttime, mechanical factors are responsible for maincharacteristics of nocturnal urban boundary layer such as elevated inversion layer over downtownarea, smaller wind speed and stronger turbulent kinetic energy (TKE) and its behavior with peak atthe top of canopy layer, whereas in the daytime, thermal factors play dominant role in the structureof UBL, such as the intensity of mixed layer and temperature in the lower atmosphere in urban area.The interaction between mechanical and thermal factors plays an important role in the formation andevolution of UBL, but its specific characteristics of mechanisms are complex. The results ofsurrounding terrain experiment show that terrain surrounding Beijing area not only determines thecharacteristic of prevailing airflow over Beijing area, but also has obvious effect on thermalstructure of UBL, such as the distribution of elevated inversion and urban heat island, and makesthem with special localization feature. The results of different extent urbanization experiment showthat with the increase in the density 展开更多
Ubiquitin(Ub)and ubiquitin-like(Ubl)pathways are critical post-translational modifications that determine whether functional proteins are degraded or activated/inactivated.To date,>600 associated enzymes have been ...Ubiquitin(Ub)and ubiquitin-like(Ubl)pathways are critical post-translational modifications that determine whether functional proteins are degraded or activated/inactivated.To date,>600 associated enzymes have been reported that comprise a hierarchical task network(e.g.,E1–E2–E3 cascade enzymatic reaction and deubiquitination)to modulate substrates,including enormous oncoproteins and tumor-suppressive proteins.Several strategies,such as classical biochemical approaches,multiomics,and clinical sample analysis,were combined to elucidate the functional relations between these enzymes and tumors.In this regard,the fundamental advances and follow-on drug discoveries have been crucial in providing vital information concerning contemporary translational efforts to tailor individualized treatment by targeting Ub and Ubl pathways.Correspondingly,emphasizing the current progress of Ub-related pathways as therapeutic targets in cancer is deemed essential.In the present review,we summarize and discuss the functions,clinical significance,and regulatory mechanisms of Ub and Ubl pathways in tumorigenesis as well as the current progress of small-molecular drug discovery.In particular,multiomics analyses were integrated to delineate the complexity of Ub and Ubl modifications for cancer therapy.The present review will provide a focused and up-to-date overview for the researchers to pursue further studies regarding the Ub and Ubl pathways targeted anticancer strategies.展开更多
Polycomb group （PcG） proteins were originally identified in Drosophila. They generally maintain gene silencing by forming multimeric complexes. Two main complexes, namely Polycomb repressive complex 2 （PRC2） and P...Polycomb group （PcG） proteins were originally identified in Drosophila. They generally maintain gene silencing by forming multimeric complexes. Two main complexes, namely Polycomb repressive complex 2 （PRC2） and PRC1, have been described. PRC2 methylates histone H3 on lysine 27 （H3K27）. PRC1, mainly composed of Polycomb （Pc）, Polyhomeotic （Ph）, Posterior sex combs （Psc） and dRing/Sce, has been shown to directly compact chromatin in vitro.展开更多
As an important horticultural plant,the orchid is widely distributed in its natural habitat and faces various environmental stresses,among which nutrient recycling and stress resistance are of great concern.During the...As an important horticultural plant,the orchid is widely distributed in its natural habitat and faces various environmental stresses,among which nutrient recycling and stress resistance are of great concern.During these processes,autophagy is an essential pathway,which is a conserved self-eating process that degrades macromolecular components and recycles cell materials or nutrients during developmental processes or under stress conditions.Two ubiquitin-like systems(UBLs)play a major role in the initiation of autophagy and are associated with two key proteins:ATG8 and ATG12.In this study,we identified and refined the UBL-related genes in orchids and performed phylogenetic reconstruction together with other plant species.We found that the orchid had unique domains in UBL-related genes,indicating potential functional diversification in the ATG8 system in plants.Transcriptome and protein tertiary structure prediction indicated that conserved domains that are vital for the canonical function of ATG12 are incomplete in orchids,in which a novel mechanism of autophagy may have evolved.展开更多
Regulation of gene expression at the post-transcriptional level is of crucial importance in the development of an organism. Here we present the characterization of a maize gene, U6 biogenesis-like 1 （UBL1）, which pl...Regulation of gene expression at the post-transcriptional level is of crucial importance in the development of an organism. Here we present the characterization of a maize gene, U6 biogenesis-like 1 （UBL1）, which plays an important role in kernel and seedling development by influencing pre-mRNA splicing. The ubll mutant, exhibiting small kernel and weak seedling, was isolated from a Mutator-tagged population. Trans- genic complementation and three independent mutant alleles confirmed that UBL1, which encodes a putative RNA exonuclease belonging to the 2H phosphodiesterase superfamily, is responsible for the phenotype of ubll. We demonstrated that UBL1 possess the RNA exonuclease activity in vitro and found that loss of UBL1 function in ubll causes decreased level and abnormal 3＇ end constitution of snRNA U6, resulting in splicing defect of mRNAs. Through the in vitro and in vivo studies replacing two histidines with alanines in the H-X-T/S-X （X is a hydrophobic residue） motifs we demonstrated that these two motifs are essential for the normal function of UBL1. We further showed that the function of UBL1 may be conserved across a wide phylogenetic distance as the heterologous expression of maize UBL1 could complement the Arabidopsis ubll mutant.展开更多
基金Supported by the Beijing Urban Environment Project (973 Project).
文摘Based on the successful simulation of a typical winter urban boundary layer(UBL) process over Beijing area during the Beijing City Air Pollution Experiment (BECAPEX) in 2001by the use of MM5 coupled with urban canopy parameterization, a series of simulation experiments areperformed to investigate the effects of urban influence, surrounding terrain, and different extentof urbanization on urban boundary layer structures over Beijing area. The results of factorseparation experiments of urban influence indicate that the total effect of urban influence, whichis the synthetic effect of urban infrastructure on thermal and dynamic structures of atmosphere, isresponsible for the formation of main UBL features over Beijing area. Meanwhile, the relativeimportance of thermal and mechanical factors of urban infrastructure and interaction between thermaland mechanical factors for the formation and evolution of UBL over the Beijing area are alsoexplored. The results show that, during nighttime, mechanical factors are responsible for maincharacteristics of nocturnal urban boundary layer such as elevated inversion layer over downtownarea, smaller wind speed and stronger turbulent kinetic energy (TKE) and its behavior with peak atthe top of canopy layer, whereas in the daytime, thermal factors play dominant role in the structureof UBL, such as the intensity of mixed layer and temperature in the lower atmosphere in urban area.The interaction between mechanical and thermal factors plays an important role in the formation andevolution of UBL, but its specific characteristics of mechanisms are complex. The results ofsurrounding terrain experiment show that terrain surrounding Beijing area not only determines thecharacteristic of prevailing airflow over Beijing area, but also has obvious effect on thermalstructure of UBL, such as the distribution of elevated inversion and urban heat island, and makesthem with special localization feature. The results of different extent urbanization experiment showthat with the increase in the density
基金National Natural Science Foundation of China (Grants 81820108022,82003297 and 22177076)Innovation Program of Shanghai Municipal Education Commission (2019-01-07-00-10-E00056,China)+2 种基金Shanghai Frontiers Science Center of Disease and Syndrome Biology of Inflammatory Cancer Transformation (2021KJ03-12,China)The Scientific and Technological Innovation Action Plan of Science and Technology Commission of Shanghai (20JC1411300,China)ChenGuang project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (19CG49,China).
文摘Ubiquitin(Ub)and ubiquitin-like(Ubl)pathways are critical post-translational modifications that determine whether functional proteins are degraded or activated/inactivated.To date,>600 associated enzymes have been reported that comprise a hierarchical task network(e.g.,E1–E2–E3 cascade enzymatic reaction and deubiquitination)to modulate substrates,including enormous oncoproteins and tumor-suppressive proteins.Several strategies,such as classical biochemical approaches,multiomics,and clinical sample analysis,were combined to elucidate the functional relations between these enzymes and tumors.In this regard,the fundamental advances and follow-on drug discoveries have been crucial in providing vital information concerning contemporary translational efforts to tailor individualized treatment by targeting Ub and Ubl pathways.Correspondingly,emphasizing the current progress of Ub-related pathways as therapeutic targets in cancer is deemed essential.In the present review,we summarize and discuss the functions,clinical significance,and regulatory mechanisms of Ub and Ubl pathways in tumorigenesis as well as the current progress of small-molecular drug discovery.In particular,multiomics analyses were integrated to delineate the complexity of Ub and Ubl modifications for cancer therapy.The present review will provide a focused and up-to-date overview for the researchers to pursue further studies regarding the Ub and Ubl pathways targeted anticancer strategies.
文摘Polycomb group （PcG） proteins were originally identified in Drosophila. They generally maintain gene silencing by forming multimeric complexes. Two main complexes, namely Polycomb repressive complex 2 （PRC2） and PRC1, have been described. PRC2 methylates histone H3 on lysine 27 （H3K27）. PRC1, mainly composed of Polycomb （Pc）, Polyhomeotic （Ph）, Posterior sex combs （Psc） and dRing/Sce, has been shown to directly compact chromatin in vitro.
文摘As an important horticultural plant,the orchid is widely distributed in its natural habitat and faces various environmental stresses,among which nutrient recycling and stress resistance are of great concern.During these processes,autophagy is an essential pathway,which is a conserved self-eating process that degrades macromolecular components and recycles cell materials or nutrients during developmental processes or under stress conditions.Two ubiquitin-like systems(UBLs)play a major role in the initiation of autophagy and are associated with two key proteins:ATG8 and ATG12.In this study,we identified and refined the UBL-related genes in orchids and performed phylogenetic reconstruction together with other plant species.We found that the orchid had unique domains in UBL-related genes,indicating potential functional diversification in the ATG8 system in plants.Transcriptome and protein tertiary structure prediction indicated that conserved domains that are vital for the canonical function of ATG12 are incomplete in orchids,in which a novel mechanism of autophagy may have evolved.
文摘Regulation of gene expression at the post-transcriptional level is of crucial importance in the development of an organism. Here we present the characterization of a maize gene, U6 biogenesis-like 1 （UBL1）, which plays an important role in kernel and seedling development by influencing pre-mRNA splicing. The ubll mutant, exhibiting small kernel and weak seedling, was isolated from a Mutator-tagged population. Trans- genic complementation and three independent mutant alleles confirmed that UBL1, which encodes a putative RNA exonuclease belonging to the 2H phosphodiesterase superfamily, is responsible for the phenotype of ubll. We demonstrated that UBL1 possess the RNA exonuclease activity in vitro and found that loss of UBL1 function in ubll causes decreased level and abnormal 3＇ end constitution of snRNA U6, resulting in splicing defect of mRNAs. Through the in vitro and in vivo studies replacing two histidines with alanines in the H-X-T/S-X （X is a hydrophobic residue） motifs we demonstrated that these two motifs are essential for the normal function of UBL1. We further showed that the function of UBL1 may be conserved across a wide phylogenetic distance as the heterologous expression of maize UBL1 could complement the Arabidopsis ubll mutant.
