In order to clarify cleavage efficiency of a multi-ribozyme expression system on their substrates,plasmids containing 20 cis-acting hammerhead ribozymes for self-cleavage and 10 trans-acting hammerhead ribozymes targe...In order to clarify cleavage efficiency of a multi-ribozyme expression system on their substrates,plasmids containing 20 cis-acting hammerhead ribozymes for self-cleavage and 10 trans-acting hammerhead ribozymes targeted on MDR1 and MRP1 substrates,the target plasmids pGEM-MDR1 and pGEM-MRP1 were constructed by employing PCR and DNA recombination.The endonuclease＇s digestion and DNA sequencing confirmed exactness of the multi-ribozyme expression systems and the target plasmids.The repeated self-cleavage tests revealed that the cisacting hammerhead ribozymes in the multi-ribozyme expression system were able to cleave themselves and trans-acting hammerhead ribozymes 196 Rz and 210 Rz were released.The cleavage efficiencies of liberated ribozymes on their targets were evaluated in vitro and the results indicate that 196 Rz and 210 Rz were able to cleave the MDR1 and MRP1 RNA substrates.The profile of cleavage reaction shows that the cleavage efficiencies were correlated with the numbers of transacting hammerhead ribozymes contained in the multi-ribozyme expression systems,as well as the multi-ribozyme system is much better than the single ribozyme.Test of various concentrations of Mg^2＋ reveals that ribozyme cleavage reactions were dependent on Mg^2＋ concentration.The plot of lg（kobs） vs.lg[Mg^2＋] displays a linear relationship in the concentration range observed（2.5―20 mmol/L）.展开更多
Dear Editor,Plant expression vectors are instrumental tools used to assess plant functional genomics and facilitate breeding improvements.Plant viruses may contain exogenous genes for replication and systemic movement...Dear Editor,Plant expression vectors are instrumental tools used to assess plant functional genomics and facilitate breeding improvements.Plant viruses may contain exogenous genes for replication and systemic movement in host plants,allowing them to be engineered into plant expression vectors for systemic and enhanced gene expression manipulation(Abrahamian et al.,2020).展开更多
Cancer immunotherapy has appeared as a prospective therapeutic modality.Therapeutic antibodies induced in an in vitro expression system act as"targeting missiles"against tumor-associated binding sites,and su...Cancer immunotherapy has appeared as a prospective therapeutic modality.Therapeutic antibodies induced in an in vitro expression system act as"targeting missiles"against tumor-associated binding sites,and subsequently,immune system attack on tumors is restored or boosted.These antibody regimens are engineered towards enhanced Fc efficacy,humanization,and fragmentation to specifically recognize and bind to effective tumor-associated targets.The challenge lies in obtaining efficient therapeutic regimens with low response rates,acquisition of resistance,and immune-related undesirable effects of artificially designed therapeutic antibodies,which is crucial for enhancing clinical efficacy.This review provides an in-depth introduction to antibodies that perform direct/indirect roles in cancer treatment by binding to immune checkpoints,costimulatory receptors,and extracellular membrane receptors.It also discusses how antibodies kill tumors and modulate microenvironment of tumor through these targets.The classification of expression systems for antibody production is summarized to guide appropriate selection based on different specificities.Understanding antibody sources,ongoing evaluation of engineered antibodies,and tumor-associated antigen research pave the way for designing appropriate antibody-based immunotherapy regimens.展开更多
基金Supported by Fund of "T. J. Martell Foundation for AIDS,Leukemia and Cancer Research"Fund of Shenzhen Bureau of Science and Technology,China(No.20008)
文摘In order to clarify cleavage efficiency of a multi-ribozyme expression system on their substrates,plasmids containing 20 cis-acting hammerhead ribozymes for self-cleavage and 10 trans-acting hammerhead ribozymes targeted on MDR1 and MRP1 substrates,the target plasmids pGEM-MDR1 and pGEM-MRP1 were constructed by employing PCR and DNA recombination.The endonuclease＇s digestion and DNA sequencing confirmed exactness of the multi-ribozyme expression systems and the target plasmids.The repeated self-cleavage tests revealed that the cisacting hammerhead ribozymes in the multi-ribozyme expression system were able to cleave themselves and trans-acting hammerhead ribozymes 196 Rz and 210 Rz were released.The cleavage efficiencies of liberated ribozymes on their targets were evaluated in vitro and the results indicate that 196 Rz and 210 Rz were able to cleave the MDR1 and MRP1 RNA substrates.The profile of cleavage reaction shows that the cleavage efficiencies were correlated with the numbers of transacting hammerhead ribozymes contained in the multi-ribozyme expression systems,as well as the multi-ribozyme system is much better than the single ribozyme.Test of various concentrations of Mg^2＋ reveals that ribozyme cleavage reactions were dependent on Mg^2＋ concentration.The plot of lg（kobs） vs.lg[Mg^2＋] displays a linear relationship in the concentration range observed（2.5―20 mmol/L）.
基金supported by the Biological Breeding of Early Maturing and Disease Resistant Cotton Varieties(grant no.2023ZD04041)the China Agricultural Research System(grant no.CARS-15-06)+1 种基金the Natural Science Foundation of Henan Province(grant no.232300421041)the Nanfan Special Project(grant nos.YBXM2316 and YBXM2441).
文摘Dear Editor,Plant expression vectors are instrumental tools used to assess plant functional genomics and facilitate breeding improvements.Plant viruses may contain exogenous genes for replication and systemic movement in host plants,allowing them to be engineered into plant expression vectors for systemic and enhanced gene expression manipulation(Abrahamian et al.,2020).
基金This work was supported by National Natural Science Foundation of China(22204015)Shenyang Young and Middle-aged Scientific and Technological Innovation Talents Project(RC220478)the Fundamental Research Funds for the Central Universities(N2405010).
文摘Cancer immunotherapy has appeared as a prospective therapeutic modality.Therapeutic antibodies induced in an in vitro expression system act as"targeting missiles"against tumor-associated binding sites,and subsequently,immune system attack on tumors is restored or boosted.These antibody regimens are engineered towards enhanced Fc efficacy,humanization,and fragmentation to specifically recognize and bind to effective tumor-associated targets.The challenge lies in obtaining efficient therapeutic regimens with low response rates,acquisition of resistance,and immune-related undesirable effects of artificially designed therapeutic antibodies,which is crucial for enhancing clinical efficacy.This review provides an in-depth introduction to antibodies that perform direct/indirect roles in cancer treatment by binding to immune checkpoints,costimulatory receptors,and extracellular membrane receptors.It also discusses how antibodies kill tumors and modulate microenvironment of tumor through these targets.The classification of expression systems for antibody production is summarized to guide appropriate selection based on different specificities.Understanding antibody sources,ongoing evaluation of engineered antibodies,and tumor-associated antigen research pave the way for designing appropriate antibody-based immunotherapy regimens.
