Construction of a recombinant lentivirus containing human microRNA-7-3 and its inhibitory effects on glioma proliferation

In the present study, we constructed a lentivirus, FIV-CMV-GFP-miR-7-3, containing the microRNA-7-3 gene and the green fluorescent protein gene, and used it to transfect human glioma U251 cells. Fluorescence microscopy showed that 80% of U251 cells expressed green fluorescence. Real-time reverse transcription PCR showed that microRNA-7-3 RNA expression in U251 cells was significantly increased. Proliferation was slowed in transfected U251 cells, and most cells were in the G1 phase of the cell cycle. In addition, the expression of the serine/threonine protein kinase 2 was decreased. Results suggested that transfection with a lentivirus carrying microRNA-7-3 can effectively suppress epidermal growth factor receptor pathway activity in U251 cells, arrest cell cycle transition from GI phase to S phase and inhibit glioma cell growth.

Isolation and Characterization of GmSTY1,a Novel Gene Encoding a Dual-Specificity Protein Kinase in Soybean（ Glycme max L.）

Phosphorylation of protein klnases has profound effects on their activity and interaction with other proteins. Tyroslne phosphorylation was reported to be involved in various physiological processes in plants; however, no typical receptor tyrosine kinase has been isolated from plants thus far. Dual-specificity kinases are potentially responsible for the phosphorylation of both tyrosine and serine/threonine of target proteins. A cDNA clone encoding a putative dual-specificity protein kinase was isolated by screening the cDNA GAL4 activation domain （AD） fusion library of soybean （Glycine max L.）, and its entire length was obtained using 5＇-rapid ampUflcatlon of cDNA ends. The predicted polypeptide of 330 amino acid residues, designated as GmSTY1, contains all 11 conserved subdomains, which share common characteristics with both the serine/ threonine and tyroslne protein klnases reported thus far. In addition, three potential N-linked glycosylation sites （NXS/T）, as well as phosphorylation motifs （SXXXS/T）, were observed, suggesting that GmSTY1 may be post-translationally modified. Furthermore, a potential N-myristoylation motif （MGARCSK） was found, suggesting that the GmSTY1 protein could associate with membranes in vivo. Southern blotting analysis revealed a single-copy of GmSTY1 in the genome. Northern blotting analysis showed that this gene was upregulated by drought and salt treatment in a time-dependent manner; however, exogenous abscisic acid （ABA） could not significantly affect the mRNA accumulation of GmSTY1. Interestingly, the transcript of this gene was remarkably downregulated by cold treatment during the early stages of the response, but upregulated later. These results Indicate that the protein kinase was possibly regulated by abiotic stresses in an ABA-independent pathway.

Cloning and Sequence Analysis of Disease Resistance Gene Analogues from Three Wild Rice Species in Yunnan

Two sets of degenerate oligonucleotide primers were designed according to amino acid conserved regions of reported plant disease resistance genes which encode proteins that contain nucleotide-binding site and leucine-rich repeats(NBS-LRR), and the plant disease resistance genes which encode serine/threonine protein kinase(STK). By polymerase chain reaction(PCR), disease resistance gene analogues have been amplified from three wild rice species in Yunnan Province, China. The DIN A fragments from amplification have been cloned into the pGEM-T vector respectively. Sequencing of the DNA fragments indicated that 7 classes, 2 classes and 6 classes NBS-LRR disease resistance gene analogues from Oryza rufipogon Griff. , Oryza officinalis Wall. , and Oryza meyeriana Baill. were obtained respectively. The two representative fragments of TO12 from Oryza officinalis Wall, and TR19 from Oryza rufipogon Griff, belong to the same class and homology of their sequences are 100%. The result shows that the sequences of the same class disease resistance gene analogues have no difference among different species of wild rice. 5 classes STK disease resistance gene analogues were also obtained among which 4 classes from Oryza rufipogon Griff. , 1 class from Oryza officinalis Wall. By comparison analysis of amino acid sequences. we found that the obtained disease resistance gene analogues have very low identity(low to 25%) with the reported disease resistance gene L6, N, Bs2, Prf, Pto, Lr10 and Xa21 etc. The finding suggests that the obtained disease resistance gene analogues are analogues of putative disease resistance genes that have not been isolated so far.

Gene Expression Profiling of the Proliferative Effect of Periplocin on Mouse Cardiac Microvascular Endothelial Cells

Objective： Periplocin is an active digitalis-like component from Cortex Periplocae, which has been widely used in the treatment of heart diseases in China for many years. According to the recommendations on the cardiovascular effect of periplocin from in vivo experiments, subsequent in vitro experiments are greatly needed for the global assessment of periplocin. The objective of this study is to investigate the cell proliferation effect and the mechanism of periplocin on endothelial cells. Methods： The proliferative activity of periplocin （0.4, 2, 10, 50, 250 pmol/L; 6, 12, 24, 48, 72 h） was investigated by a comparison with the well-reported cardiac glycoside, ouabain, on mouse cardiac microvascular endothelial cells （CMEC）. 3-（4,5-dimethylthiazolyl）- 2,5-diphenyltetrazolium bromide （MTT）, lactate dehydrogenase （LDH） and 5-bromo-2-deoxyuridine （BrdU） assays were used to evaluate cell proliferation and viability. Subsequently, cDNA microarray experiments were performed on periplocin- （50 pmol/L） and ouabain- （50 pmol/L） treated cells, and data was analyzed by ArrayTrack software. Results： Periplocin could increase cell viability to a level lower than ouabain in the MIF analysis, but decrease LDH release simultaneously. The BrdU incorporation assay showed an increase in cell proliferation with 2-50 μmol/L periplocin. Genes related to protein serine/threonine kinase were the most significantly enriched in the 160 genes identified in periplocin versus the control. In the 165 genes regulated by periplocin versus ouabain, GTP-binding was the most altered term. Conclusions： The results demonstrated the proliferation action of periplocin on CMEC. Meanwhile, its lower cytotoxicity compared to ouabain provides a new insight into the treatment of heart failure.