Tension wood(TW)is a specialized xylem tissue formed in angiosperm trees under gravitational stimulus or mechanical stresses(e.g.,bending).The genetic regulation that underlies this important mechanism remains poorly ...Tension wood(TW)is a specialized xylem tissue formed in angiosperm trees under gravitational stimulus or mechanical stresses(e.g.,bending).The genetic regulation that underlies this important mechanism remains poorly understood.Here,we used laser capture microdissection of stem xylem cells coupled with full transcriptome RNA-sequencing to analyze TW formation in Populus trichocarpa.After tree bending,PtrLBD39 was the most significantly induced transcription factor gene;it has a phylogenetically paired homolog,PtrLBD22.CRISPR-based knockout of PtrLBD39/22 severely inhibited TW formation,reducing cellulose and increasing lignin content.Transcriptomic analyses of CRISPR-based PtrLBD39/22 double mutants showed that these two genes regulate a set of TW-related genes.Chromatin immunoprecipitation sequencing(ChIP-seq)was used to identify direct targets of PtrLBD39.We integrated transcriptomic analyses and ChIP-seq assays to construct a transcriptional regulatory network(TRN)mediated by PtrLBD39.In this TRN,PtrLBD39 directly regulates 26 novel TW-responsive transcription factor genes.Our work suggests that PtrLBD39 and PtrLBD22 specifically control TW formation by mediating a TW-specific TRN in Populus.展开更多
Establishing the hepatoma cell-specific expression of human interferon gene mediated by retroviral vectors. Methods: Human interferon-β complementary DNA (IFN-β cDNA) was inserted into polylinker site of pMNSM retro...Establishing the hepatoma cell-specific expression of human interferon gene mediated by retroviral vectors. Methods: Human interferon-β complementary DNA (IFN-β cDNA) was inserted into polylinker site of pMNSM retroviral vector to construct recombinant retroviral vector pMNSIFNB, where the transcription of IFN-β gene was driven by SV40 early region promoter, and MNAIFNB, where the transcription of IFN-β gene was driven by SV40 early region promoter regulated by α-fetoprotein enhancer. The retroviral constructs were respectively introduced into PA317 amphotropic packaging cells by means of lipofectamine mediated gene transfer procedure. The plasmids transfection efficiency was among (4-25)ｘ103 colonies/μg DNA/106 PA317 cells. The retrovirus infection efficiency was among (4. 5-500)ｘ104 Colony Forming Units (CFU)/ml. The recombinant retroviruses were used to infect human hepatoma cells, renal cell carcinoma cells and melanoma cell lines in the presence of 4 μg/ml polybrene. Results: Dot hybridization of total RNA from the neomycin resistant colonies and interferon expression assay indicated that human α-fetoprotein enhancer induced efficient and specific transcription and expression of IFN-β gene driven by the promoter of different origin in human hepatoma cells by which α-fetoprotein was highly produced. Conclusion: Cis-active element of α-fetoprotein gene can drive IFN-β gene specifically expressed in human hepatoma cells, which presents some valuable materials for the hepatoma-specific immune gene therapy.展开更多
OBJECTIVE: To screen the 5' regulatory region of the aldose reductase (AR) gene for genetic variabilities causing changes in protein expression and affecting the promoter function. METHODS: The screenings were car...OBJECTIVE: To screen the 5' regulatory region of the aldose reductase (AR) gene for genetic variabilities causing changes in protein expression and affecting the promoter function. METHODS: The screenings were carried out by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). All SSCP variants were submitted for DNA sequencing and inserted into the plasmid chloromycetin acetyl transferase (CAT) enhancer vector. The constructs were used to transfect Hela cells, and CAT assays were performed to assess promoter activity. Gel mobility shift and footprinting assays were also performed to determine the interaction between the DNA and nuclear proteins. RESULTS: Two polymorphisms, C (-106) T and C (-12) G, were identified in the regulatory region in 123 Chinese control subjects and 145 patients with type 2 diabetes mellitus. The frequencies of genotypes WT/WT, WT/C (-12) G and WT/C (-106) T were not significantly different between the subjects and patients. In the patients with and without retinopathy, frequencies of WT/C (-106) T were 31.5% and 17.5% (P 0.05) respectively. The total frequency of WT/C (-12) G and WT/C (-106) T in patients with retinopathy was 41.8%, significantly higher than that (20.0%) in patients without retinopathy (P展开更多
基金This work was supported by the National Key Research and Development Program of China(no.2016YFD0600106)We also acknowledge financial support from the National Natural Science Foundation of China(grant nos.32001332 and 32001331)+1 种基金the Fundamental Research Funds for the Central Universities of China(grant nos.2572018CL01 and 2572018CL02)the Heilongjiang Touyan Innovation Team Program(Tree Genetics and Breeding Innovation Team).
文摘Tension wood(TW)is a specialized xylem tissue formed in angiosperm trees under gravitational stimulus or mechanical stresses(e.g.,bending).The genetic regulation that underlies this important mechanism remains poorly understood.Here,we used laser capture microdissection of stem xylem cells coupled with full transcriptome RNA-sequencing to analyze TW formation in Populus trichocarpa.After tree bending,PtrLBD39 was the most significantly induced transcription factor gene;it has a phylogenetically paired homolog,PtrLBD22.CRISPR-based knockout of PtrLBD39/22 severely inhibited TW formation,reducing cellulose and increasing lignin content.Transcriptomic analyses of CRISPR-based PtrLBD39/22 double mutants showed that these two genes regulate a set of TW-related genes.Chromatin immunoprecipitation sequencing(ChIP-seq)was used to identify direct targets of PtrLBD39.We integrated transcriptomic analyses and ChIP-seq assays to construct a transcriptional regulatory network(TRN)mediated by PtrLBD39.In this TRN,PtrLBD39 directly regulates 26 novel TW-responsive transcription factor genes.Our work suggests that PtrLBD39 and PtrLBD22 specifically control TW formation by mediating a TW-specific TRN in Populus.
文摘Establishing the hepatoma cell-specific expression of human interferon gene mediated by retroviral vectors. Methods: Human interferon-β complementary DNA (IFN-β cDNA) was inserted into polylinker site of pMNSM retroviral vector to construct recombinant retroviral vector pMNSIFNB, where the transcription of IFN-β gene was driven by SV40 early region promoter, and MNAIFNB, where the transcription of IFN-β gene was driven by SV40 early region promoter regulated by α-fetoprotein enhancer. The retroviral constructs were respectively introduced into PA317 amphotropic packaging cells by means of lipofectamine mediated gene transfer procedure. The plasmids transfection efficiency was among (4-25)ｘ103 colonies/μg DNA/106 PA317 cells. The retrovirus infection efficiency was among (4. 5-500)ｘ104 Colony Forming Units (CFU)/ml. The recombinant retroviruses were used to infect human hepatoma cells, renal cell carcinoma cells and melanoma cell lines in the presence of 4 μg/ml polybrene. Results: Dot hybridization of total RNA from the neomycin resistant colonies and interferon expression assay indicated that human α-fetoprotein enhancer induced efficient and specific transcription and expression of IFN-β gene driven by the promoter of different origin in human hepatoma cells by which α-fetoprotein was highly produced. Conclusion: Cis-active element of α-fetoprotein gene can drive IFN-β gene specifically expressed in human hepatoma cells, which presents some valuable materials for the hepatoma-specific immune gene therapy.
文摘OBJECTIVE: To screen the 5' regulatory region of the aldose reductase (AR) gene for genetic variabilities causing changes in protein expression and affecting the promoter function. METHODS: The screenings were carried out by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). All SSCP variants were submitted for DNA sequencing and inserted into the plasmid chloromycetin acetyl transferase (CAT) enhancer vector. The constructs were used to transfect Hela cells, and CAT assays were performed to assess promoter activity. Gel mobility shift and footprinting assays were also performed to determine the interaction between the DNA and nuclear proteins. RESULTS: Two polymorphisms, C (-106) T and C (-12) G, were identified in the regulatory region in 123 Chinese control subjects and 145 patients with type 2 diabetes mellitus. The frequencies of genotypes WT/WT, WT/C (-12) G and WT/C (-106) T were not significantly different between the subjects and patients. In the patients with and without retinopathy, frequencies of WT/C (-106) T were 31.5% and 17.5% (P 0.05) respectively. The total frequency of WT/C (-12) G and WT/C (-106) T in patients with retinopathy was 41.8%, significantly higher than that (20.0%) in patients without retinopathy (P
