AFF1 and AFF4 belong to the AFF （AF4/FMR2） family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b （P-TEFb） and ELL1/2, in su...AFF1 and AFF4 belong to the AFF （AF4/FMR2） family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b （P-TEFb） and ELL1/2, in super elongation complexes （SECs）. Both AFF1 and AFF4 regulate gene transcription through elongation and chromatln remodeling. However, their function in the osteogenic differentiation of mesenchymal stem cells （MSCs） is unknown. In this study, we show that small interfering RNA （siRNA）-mediated depletion of AFF1 in human MSCs leads to increased alkaline phosphatase （ALP） activity, enhanced mineralization and upregulated expression of osteogenic-related genes. On the contrary, depletion of AFF4 significantly inhibits the osteogenic potential of MSCs. In addition, we confirm that overexpression of AFF1 and AFF4 differentially affects osteogenic differentiation in vitro and MSC-mediated bone formation in vivo. Mechanistically, we find that AFFI regulates the expression of DKK1 via binding to its promoter region. Depletion of DKK1 in HA-AFFl-overexpressing MSCs abrogates the impairment of osteogenic differentiation. Moreover, we detect that AFF4 is enriched in the promoter region of ID1. AFF4 knockdown blunts the BRE luciferase activity, SP7 expression and ALP activity induced by BMP2 treatment. In conclusion, our data indicate that AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.AFF1 and AFF4 belong to the AFF （AF4/FMR2） family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b （P-TEFb） and ELL1/2, in super elongation complexes （SECs）. Both AFFI and AFF4 regulate gene transcription through elongation and chromatln remodeling. However, their function in the osteogenic differentiation of mesenchymal stem cells （MSCs） is unknown. In this study, we show that small interfering RNA （siRNA）-mediated depletion of AFF1 in human MSCs leads to increased alkaline phosphatase （ALP） activity, enhanced mineralization and upregulated expression of osteogenic-related genes. On the contrary, depletion of AFF4 significantly inhibits the osteogenic potential of MSCs. In addition, we confirm that overexpression of AFF1 and AFF4 differentially affects osteogenic differentiation in vitro and MSC-mediated bone formation in vivo. Mechanistically, we find that AFFI regulates the expression of DKK1 via binding to its promoter region. Depletion of DKK1 in HA-AFFl-overexpressing MSCs abrogates the impairment of osteogenic differentiation. Moreover, we detect that AFF4 is enriched in the promoter region of ID1. AFF4 knockdown blunts the BRE luciferase activity, SP7 expression and ALP activity induced by BMP2 treatment. In conclusion, our data indicate that AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.展开更多
The super elongation complex(SEC)containing positive transcription elongation factor b plays a critical role in regulating transcription elongation.AFF1 and AFF4,two members of the AF4/FMR2 family,act as central scaff...The super elongation complex(SEC)containing positive transcription elongation factor b plays a critical role in regulating transcription elongation.AFF1 and AFF4,two members of the AF4/FMR2 family,act as central scaffold proteins of SEC and are associated with various human diseases.However,their precise roles in transcriptional control remain unclear.Here,we investigate differences in the genomic distribution patterns of AFF1 and AFF4 around transcription start sites(TSSs).AFF1 mainly binds upstream of the TSS,while AFF4 is enriched downstream of the TSS.Notably,disruption of AFF4 results in slow elongation and early termination in a subset of AFF4-bound active genes,whereas AFF1 deletion leads to fast elongation and transcriptional readthrough in the same subset of genes.Additionally,AFF1 knockdown increases AFF4 levels at chromatin,and vice versa.In summary,these findings demonstrate that AFF1 and AFF4 function antagonistically to regulate RNA polymerase Ⅱ transcription.展开更多
Privacy preservation(PP)in Digital forensics(DF)is a conflicted and non-trivial issue.Existing solutions use the searchable encryption concept and,as a result,are not efficient and support only a keyword search.Moreov...Privacy preservation(PP)in Digital forensics(DF)is a conflicted and non-trivial issue.Existing solutions use the searchable encryption concept and,as a result,are not efficient and support only a keyword search.Moreover,the collected forensic data cannot be analyzed using existing well-known digital tools.This research paper first investigates the lawful requirements for PP in DF based on the organization for economic co-operation and development OECB)privacy guidelines.To have an efficient investigation process and meet the increased volume of data,the presented framework is designed based on the selective imaging concept and advanced encryption standard(AES).The proposed framework has two main modules,namely Selective Imaging Module(SIM)and Selective Analysis Module(SAM).The SIM and SAM modules are implemented based on advanced forensic format 4(AFF4)and SleuthKit open source forensics frameworks,respectively,and,accordingly,the proposed framework is evaluated in a forensically sound manner.The evaluation result is compared with other relevant works and,as a result,the proposed solution provides a privacy-preserving,efficient forensic imaging and analysis process while having also sufficient methods.Moreover,the AFF4 forensic image,produced by the SIM module,can be analyzed not only by SAM,but also by other well-known analysis tools available on the market.展开更多
基金supported by grants from the National Natural Science Foundation of China(NSFC,81722014,81571001,81500354,and 81621062)Sichuan Province Science and Technology Innovation Team Program(2017TD0016)State Key Laboratory of Oral Diseases(SKLOD201704)
文摘AFF1 and AFF4 belong to the AFF （AF4/FMR2） family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b （P-TEFb） and ELL1/2, in super elongation complexes （SECs）. Both AFF1 and AFF4 regulate gene transcription through elongation and chromatln remodeling. However, their function in the osteogenic differentiation of mesenchymal stem cells （MSCs） is unknown. In this study, we show that small interfering RNA （siRNA）-mediated depletion of AFF1 in human MSCs leads to increased alkaline phosphatase （ALP） activity, enhanced mineralization and upregulated expression of osteogenic-related genes. On the contrary, depletion of AFF4 significantly inhibits the osteogenic potential of MSCs. In addition, we confirm that overexpression of AFF1 and AFF4 differentially affects osteogenic differentiation in vitro and MSC-mediated bone formation in vivo. Mechanistically, we find that AFFI regulates the expression of DKK1 via binding to its promoter region. Depletion of DKK1 in HA-AFFl-overexpressing MSCs abrogates the impairment of osteogenic differentiation. Moreover, we detect that AFF4 is enriched in the promoter region of ID1. AFF4 knockdown blunts the BRE luciferase activity, SP7 expression and ALP activity induced by BMP2 treatment. In conclusion, our data indicate that AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.AFF1 and AFF4 belong to the AFF （AF4/FMR2） family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b （P-TEFb） and ELL1/2, in super elongation complexes （SECs）. Both AFFI and AFF4 regulate gene transcription through elongation and chromatln remodeling. However, their function in the osteogenic differentiation of mesenchymal stem cells （MSCs） is unknown. In this study, we show that small interfering RNA （siRNA）-mediated depletion of AFF1 in human MSCs leads to increased alkaline phosphatase （ALP） activity, enhanced mineralization and upregulated expression of osteogenic-related genes. On the contrary, depletion of AFF4 significantly inhibits the osteogenic potential of MSCs. In addition, we confirm that overexpression of AFF1 and AFF4 differentially affects osteogenic differentiation in vitro and MSC-mediated bone formation in vivo. Mechanistically, we find that AFFI regulates the expression of DKK1 via binding to its promoter region. Depletion of DKK1 in HA-AFFl-overexpressing MSCs abrogates the impairment of osteogenic differentiation. Moreover, we detect that AFF4 is enriched in the promoter region of ID1. AFF4 knockdown blunts the BRE luciferase activity, SP7 expression and ALP activity induced by BMP2 treatment. In conclusion, our data indicate that AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.
基金supported by grants from the National Key R&D Program of China(2018YFA0800100 to C.L.,2018YFA0800103 to Z.L.)the National Natural Science Foundation of China(32030017 and 31970617 to C.L.,31970626 to Z.L.)Shenzhen Science and Technology Program(JCYJ20210324133602008 to C.L.,JCYJ20210324133601005 to Z.L.).
文摘The super elongation complex(SEC)containing positive transcription elongation factor b plays a critical role in regulating transcription elongation.AFF1 and AFF4,two members of the AF4/FMR2 family,act as central scaffold proteins of SEC and are associated with various human diseases.However,their precise roles in transcriptional control remain unclear.Here,we investigate differences in the genomic distribution patterns of AFF1 and AFF4 around transcription start sites(TSSs).AFF1 mainly binds upstream of the TSS,while AFF4 is enriched downstream of the TSS.Notably,disruption of AFF4 results in slow elongation and early termination in a subset of AFF4-bound active genes,whereas AFF1 deletion leads to fast elongation and transcriptional readthrough in the same subset of genes.Additionally,AFF1 knockdown increases AFF4 levels at chromatin,and vice versa.In summary,these findings demonstrate that AFF1 and AFF4 function antagonistically to regulate RNA polymerase Ⅱ transcription.
基金The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through research group no(RG-1441-531).
文摘Privacy preservation(PP)in Digital forensics(DF)is a conflicted and non-trivial issue.Existing solutions use the searchable encryption concept and,as a result,are not efficient and support only a keyword search.Moreover,the collected forensic data cannot be analyzed using existing well-known digital tools.This research paper first investigates the lawful requirements for PP in DF based on the organization for economic co-operation and development OECB)privacy guidelines.To have an efficient investigation process and meet the increased volume of data,the presented framework is designed based on the selective imaging concept and advanced encryption standard(AES).The proposed framework has two main modules,namely Selective Imaging Module(SIM)and Selective Analysis Module(SAM).The SIM and SAM modules are implemented based on advanced forensic format 4(AFF4)and SleuthKit open source forensics frameworks,respectively,and,accordingly,the proposed framework is evaluated in a forensically sound manner.The evaluation result is compared with other relevant works and,as a result,the proposed solution provides a privacy-preserving,efficient forensic imaging and analysis process while having also sufficient methods.Moreover,the AFF4 forensic image,produced by the SIM module,can be analyzed not only by SAM,but also by other well-known analysis tools available on the market.
