N-ros is one of the transforming genes in human hepatic cancer cells. It has been found that N-ras was overexpressed at the mENA and protein level in hepatoma cells. In order to explore the biological roles of N-ras i...N-ros is one of the transforming genes in human hepatic cancer cells. It has been found that N-ras was overexpressed at the mENA and protein level in hepatoma cells. In order to explore the biological roles of N-ras in human hepatic oaroinogenesis and the potential application in control of cancer cell growth, a pseudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged. A recombinant rebrovirus vector containing antisense or sense sequences of N-ras oDNA was constructed by pZIP-NeoSV(X)1. The pseudotype virus was packaged and rescued by transfeotion and infection in PA317 and ψ2 helper cells. It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PEF/5 hepatoma cells accompanied with inhibition of p21 expression, while the retrovirus containing sense sequence had none. The pseudotype virus had no effect on human diploid fibroblasts.展开更多
Retina is a multilayer and highly specialized tissue important in converting light into neural signals. In humans, the critical period for the formation of complex multiplayer structure takes place during embryogenesi...Retina is a multilayer and highly specialized tissue important in converting light into neural signals. In humans, the critical period for the formation of complex multiplayer structure takes place during embryogenesis be- tween 12 and 28 weeks. The morphologic changes during retinal development in humans have been studied but little is known about the molecular events essential for the formation of the retina. To gain further insights into this process, cDNA microarrays containing 16361 human gene probes were used to measure the gene expression levels in retinas. Of the 16361 genes, 68.7%, 71.4% and 69.7% showed positive hybridiza- tion with cDNAs made from 12—16 week fetal, 22—26 week fetal and adult retinas. A total of 814 genes showed a mini- mum of 3-fold changes between the lowest and highest ex- pression levels among three time points and among them, 106 genes had expression levels with the hybridization intensity above 100 at one or more time points. The clustering analysis suggested that the majority of differentially expressed genes were down-regulated during the retinal development. The differentially expressed genes were further classified accord- ing to functions of known genes, and were ranked in de- creasing order according to frequency: development, differ- entiation, signal transduction, protein synthesis and transla- tion, metabolism, DNA binding and transcription, DNA syn- thesis-repair-recombination, immuno-response, ion channel- transport, cell receptor, cytoskeleton, cell cycle, pro-oncogene, stress and apoptosis related genes. Among these 106 differen- tially expressed genes, 60 are already present in NEI retina cDNA or EST Databank but the remaining 46 genes are ab- sent and thus identified as “function unknown”. To validate gene expression data from the microarray, real-time RT-PCR was performed for 46 “function unknown” genes and 6 known retina specific expression genes, and β-actin was used as internal control. Twenty-seven of these genes showed very similar expression prof展开更多
文摘N-ros is one of the transforming genes in human hepatic cancer cells. It has been found that N-ras was overexpressed at the mENA and protein level in hepatoma cells. In order to explore the biological roles of N-ras in human hepatic oaroinogenesis and the potential application in control of cancer cell growth, a pseudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged. A recombinant rebrovirus vector containing antisense or sense sequences of N-ras oDNA was constructed by pZIP-NeoSV(X)1. The pseudotype virus was packaged and rescued by transfeotion and infection in PA317 and ψ2 helper cells. It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PEF/5 hepatoma cells accompanied with inhibition of p21 expression, while the retrovirus containing sense sequence had none. The pseudotype virus had no effect on human diploid fibroblasts.
文摘Retina is a multilayer and highly specialized tissue important in converting light into neural signals. In humans, the critical period for the formation of complex multiplayer structure takes place during embryogenesis be- tween 12 and 28 weeks. The morphologic changes during retinal development in humans have been studied but little is known about the molecular events essential for the formation of the retina. To gain further insights into this process, cDNA microarrays containing 16361 human gene probes were used to measure the gene expression levels in retinas. Of the 16361 genes, 68.7%, 71.4% and 69.7% showed positive hybridiza- tion with cDNAs made from 12—16 week fetal, 22—26 week fetal and adult retinas. A total of 814 genes showed a mini- mum of 3-fold changes between the lowest and highest ex- pression levels among three time points and among them, 106 genes had expression levels with the hybridization intensity above 100 at one or more time points. The clustering analysis suggested that the majority of differentially expressed genes were down-regulated during the retinal development. The differentially expressed genes were further classified accord- ing to functions of known genes, and were ranked in de- creasing order according to frequency: development, differ- entiation, signal transduction, protein synthesis and transla- tion, metabolism, DNA binding and transcription, DNA syn- thesis-repair-recombination, immuno-response, ion channel- transport, cell receptor, cytoskeleton, cell cycle, pro-oncogene, stress and apoptosis related genes. Among these 106 differen- tially expressed genes, 60 are already present in NEI retina cDNA or EST Databank but the remaining 46 genes are ab- sent and thus identified as “function unknown”. To validate gene expression data from the microarray, real-time RT-PCR was performed for 46 “function unknown” genes and 6 known retina specific expression genes, and β-actin was used as internal control. Twenty-seven of these genes showed very similar expression prof
