摘要：AIM： TO inhibit the expression of vascular endothelial growth factor （VEGF） in colon cancer cell line by rna interference （rnai）.METHODS： Followed the service of E-rnai, we designed and constructed two kinds of shrna expression vectors aiming at the VEGF gene, then transfected them into colon cancer HT29 cells by lipofectamineTM 2000. The level of VEGF mrna was investigated by RT-PCR and Northern blotting. The protein expression of VEGF was observed by immunofluoresence staining and Western blotting.RESULTS： We got two kinds of VEGF specific shrna expression vectors which could efficiently inhibit the expression of VEGF in HT29 cells. RT-PCR, Northern blotting, immunofluoresence staining and Western blotting showed that inhibition rate for VEGF expression was up to 42%, 89%, 73% and 82%, respectively.CONCLUSION： The expression of VEGF can be inhibited by rna interference in HT29 cells.

摘要：Objective To silence the expression of α-synuclein in MN9D dopaminergic cells using vector mediated rna interference （rnai） and examined its effects on cell proliferation and viability. Methods We identified two 19-nucleotide stretches within the coding region of the α-synuclein gene and designed three sets of oligonucleotides to generate doublestranded （ds） oligos. The ds oligos were inserted into the pENTR^TM/Hl/TO vector and transfected into MN9D dopaminergic cells, α-Synuclein expression was detected by RT-PCR, real-time PCR, immunocytochemistry staining and Western blot. In addition, we measured cell proliferation using growth curves and cell viability by 3-（4, 5）-dimethylthiahiazo （-z-y 1）-3, 5-diphenytetrazoliumromide （M＇FF）. Results The mrna and protein levels of α-synuclein gene were significantly down-regulated in pSH2/α-SYN-transfected cells compared with control MN9D and pSH/CON-transfected MN9D cells, while pSHI/α-SYN- transfected cells showed no significant difference. Silencing α-synuclein expression does not affect cell proliferation but may decrease cell viability. Conclusion Our results demonstrated pSH2/α-SYN is an effective small interfering rna （sirna） sequence and potent silencing of mouse α-synuclein expression in MN9D cells by vector-based rnai, which provides the tools for studying the normal function of α-synuclein and examining its role in Parkinson＇s disease （PD） pathogenesis. α-Synuclein may be important for the viability of MN9D cells, and loss of α-synuclein may induce cell injury directly or indirectl

摘要：Previously, a moderately repetitive DNA sequence （RRD3） was cloned from rice （Oryza sativa L.） by DNA renaturation kinetics. Sequence analysis revealed several conserved promoter motifs, including four TATA-boxes and a CAAT-box, and promoter activity was shown in Escherichia coli and mammalian expression systems. Here, we inserted the RRD3 fragment into the plant promoter-capture vector, pCAMBIA1391Z, and examined whether the RRD3 fragment has promoter activity in plants. Transgenic tobacco and rice calli both showed β-glucuronidase （GUS） activity, indicating that RRD3 can act as a promoter in both monocot and dicot plants. Based on the promoter characteristic of RRD3, we designed a plant universal binary vector, pCRiRRD3, which is suitable for performing researches on plant rna interference. This vector has two multiple cloning sites to facilitate sense and antisense cloning of the target sequence, separated by an intron fragment of 200 bp. The efficiency of the vector for gene silencing was assayed by histochemical and quantitative fluorometric GUS assays in transgenic tobacco. These research results suggested that this plant rnai vector pCRiRRD3 can effectively perform gene silencing researches on both monocot and dicot plants.

摘要：In the application of rnai technology,it is an essential step to design siR NA applicable to target *** present,there are many researches and conclusions on siR NA *** paper aims to the influences of mR NA secondary structure or siR NA antisense-strand secondary structure on siR NA silence *** paper also discusses the problems and sets out further insights in the research.