Expression-independent gene or polyadenylation[poly（A）]trapping is a powerful tool for genome-wide mutagenesis regardless of whether a targeted gene is expressed.Although a number of poly（A）-trap vectors have been...Expression-independent gene or polyadenylation[poly（A）]trapping is a powerful tool for genome-wide mutagenesis regardless of whether a targeted gene is expressed.Although a number of poly（A）-trap vectors have been developed for the capture and mutation of genes across a vertebrate genome,further efforts are needed to avoid the 3＇-terminal insertion bias and the splice donor（SD） read-through,and to improve the mutagenicity.Here,we present a Sleeping Beauty（SB） transposon-based vector that can overcome these limitations through the inclusion of three functional cassettes required for gene-finding,gene-breaking and large-scale mutagenesis, respectively.The functional cassette contained a reporter/selective marker gene driven by a constitutive promoter in front of a strong SD signal and an AU-rich RNA-destabilizing element（ARE）,which greatly reduced the SD read-through events,except that the internal ribosomal entry site（IRES） element was introduced in front of the SD signal to overcome the phenomenon of 3＇-bias gene trapping.The breaking cassette consisting of an enhanced splicing acceptor（SA）,a poly（A） signal coupled with a transcriptional terminator（TT） effectively disrupted the transcription of trapped genes.Moreover,the Hsp70 promoter from tilapia genome was employed to drive the inducible expression of SB11,which allows the conditional remobilization of a trap insert from a non-coding region.The combination of three cassettes led to effective capture and disruption of endogenous genes in HeLa cells.In addition,the Cre/LoxP system was introduced to delete the Hsp70-SB11 cassette for stabilization of trapped gene interruption and biosafety. Thus,this poly（A）-trap vector is an alternative and effective tool for identification and mutation of endogenous genes in cells and animals.展开更多
Purpose:New developments in the study of delayed recognition are discussed.Design/methodology/approach:Based on these new developments a method is proposed to characterize delayed recognition as a fuzzy concept.Findin...Purpose:New developments in the study of delayed recognition are discussed.Design/methodology/approach:Based on these new developments a method is proposed to characterize delayed recognition as a fuzzy concept.Findings:A benchmark value of 0.333 corresponding with linear growth is obtained.Moreover,a case is discovered in which an expert found delayed recognition several years before citation analysis could discover this phenomenon.Research limitations:As all citation studies also this one is database dependent.Practical implications:Delayed recognition is turned into a fuzzy concept.Originality/value:The article presents a new way of studying delayed recognition.展开更多
Cancer gene discovery continues to drive current cancer research with the promise of identifying new diagnostic markers and therapeutic targets by elucidating novel genetic interactions that promote or sustain tumor f...Cancer gene discovery continues to drive current cancer research with the promise of identifying new diagnostic markers and therapeutic targets by elucidating novel genetic interactions that promote or sustain tumor formation. Sleeping Beauty（SB） transposoniated insertional mutagenesis has emerged as an exciting approach to identify novel cancer-causing genes in the mouse. The SB transposon faithfully ＂hops＂ throughout the genome by a cut-and-paste mechanism mediated by the ubiquitous expression of the SB transposase. Initial tumor data generated using an SB transposon harboring the MSCV promoter demonstrated a bias towards hematopoietic tumors. More recently, experiments using a modified SB transposon containing the CAG promoter have generated cohorts of mice with solid tumors, primarily carcinomas, which in some cases metastasize. Many animals also develop multiple, inde- pendent primary tumors. These data demonstrate the utility of the SB transposition system for cancer gene discovery across organ systems.展开更多
Gene therapy offers important perspectives in current and future medicine but suffers from imperfect vectors for the delivery of the therapeutic gene. Most preclinical and clinical trials have been based on the use of...Gene therapy offers important perspectives in current and future medicine but suffers from imperfect vectors for the delivery of the therapeutic gene. Most preclinical and clinical trials have been based on the use of viral vectors, which have evident advantages but also some serious disadvantages. In the past decade the use of DNA transposon-based systems for gene delivery has emerged as a non-viral alternative. DNA transposon vector engineering remains largely in a preclinical phase but some interesting results have been obtained. This mini-review aims to provide the current state of the art on DNA transposon vectors used in a gene therapy perspective.展开更多
基金supported by the National Natural Science Foundation of China(No.30871442) to Z.Cuithe National Basic Research Program of China(No.2012CB944500)
文摘Expression-independent gene or polyadenylation[poly（A）]trapping is a powerful tool for genome-wide mutagenesis regardless of whether a targeted gene is expressed.Although a number of poly（A）-trap vectors have been developed for the capture and mutation of genes across a vertebrate genome,further efforts are needed to avoid the 3＇-terminal insertion bias and the splice donor（SD） read-through,and to improve the mutagenicity.Here,we present a Sleeping Beauty（SB） transposon-based vector that can overcome these limitations through the inclusion of three functional cassettes required for gene-finding,gene-breaking and large-scale mutagenesis, respectively.The functional cassette contained a reporter/selective marker gene driven by a constitutive promoter in front of a strong SD signal and an AU-rich RNA-destabilizing element（ARE）,which greatly reduced the SD read-through events,except that the internal ribosomal entry site（IRES） element was introduced in front of the SD signal to overcome the phenomenon of 3＇-bias gene trapping.The breaking cassette consisting of an enhanced splicing acceptor（SA）,a poly（A） signal coupled with a transcriptional terminator（TT） effectively disrupted the transcription of trapped genes.Moreover,the Hsp70 promoter from tilapia genome was employed to drive the inducible expression of SB11,which allows the conditional remobilization of a trap insert from a non-coding region.The combination of three cassettes led to effective capture and disruption of endogenous genes in HeLa cells.In addition,the Cre/LoxP system was introduced to delete the Hsp70-SB11 cassette for stabilization of trapped gene interruption and biosafety. Thus,this poly（A）-trap vector is an alternative and effective tool for identification and mutation of endogenous genes in cells and animals.
文摘Purpose:New developments in the study of delayed recognition are discussed.Design/methodology/approach:Based on these new developments a method is proposed to characterize delayed recognition as a fuzzy concept.Findings:A benchmark value of 0.333 corresponding with linear growth is obtained.Moreover,a case is discovered in which an expert found delayed recognition several years before citation analysis could discover this phenomenon.Research limitations:As all citation studies also this one is database dependent.Practical implications:Delayed recognition is turned into a fuzzy concept.Originality/value:The article presents a new way of studying delayed recognition.
文摘Cancer gene discovery continues to drive current cancer research with the promise of identifying new diagnostic markers and therapeutic targets by elucidating novel genetic interactions that promote or sustain tumor formation. Sleeping Beauty（SB） transposoniated insertional mutagenesis has emerged as an exciting approach to identify novel cancer-causing genes in the mouse. The SB transposon faithfully ＂hops＂ throughout the genome by a cut-and-paste mechanism mediated by the ubiquitous expression of the SB transposase. Initial tumor data generated using an SB transposon harboring the MSCV promoter demonstrated a bias towards hematopoietic tumors. More recently, experiments using a modified SB transposon containing the CAG promoter have generated cohorts of mice with solid tumors, primarily carcinomas, which in some cases metastasize. Many animals also develop multiple, inde- pendent primary tumors. These data demonstrate the utility of the SB transposition system for cancer gene discovery across organ systems.
文摘Gene therapy offers important perspectives in current and future medicine but suffers from imperfect vectors for the delivery of the therapeutic gene. Most preclinical and clinical trials have been based on the use of viral vectors, which have evident advantages but also some serious disadvantages. In the past decade the use of DNA transposon-based systems for gene delivery has emerged as a non-viral alternative. DNA transposon vector engineering remains largely in a preclinical phase but some interesting results have been obtained. This mini-review aims to provide the current state of the art on DNA transposon vectors used in a gene therapy perspective.
