ABSTRACT
Objective To study the effects of semaphorin 5A (SEMA5A) gene silencing by lentivirus?mediated short hairpin RNA(shRNA)on biological activity of malignant melanoma cell line A375. Methods Two pairs of interference sequences for SEMA5A gene(shRNA1 and A375?shRNA2)and a pair of control interference sequences were designed to build lentiviral vectors, which were then transfected into HEK293T cells to gain lentivirus. A375 cells were divided into three groups:experimental group(A375?shRNA1 and A375?shRNA2 cells)transfected with the lentivirus containing shRNA1 or shRNA2, negative control group (A375?con cells) transfected with that containing the control shRNA, and blank control group(A375 cells)receiving no transfection. The A375 cells with stable knockdown of SEMA5A gene expression were screened by puromycin. Subsequently, reverse transcription?PCR and Western?blot analysis were performed to detect mRNA and protein expressions of Semaphorin 5A in these cells, and methyl thiazolyl tetrazolium(MTT)assay was applied to evaluate the growth of cells. The scratch assay and invasion assay were conducted to estimate migration and invasion ability of cells. Results The lentivirus containing the SEMA5A?targeting shRNAs or control shRNA was successfully transfected into A375 cells, and stably transfected cells were gained after puromycin selection. The expressions of semaphorin 5A mRNA and protein in the A375?shRNA2 cells were significantly reduced compared with those in the A375?con and A375 cells(all P 0.05). The scratch assay showed that there was no obvious cell migration into the scratch in the experiment group, whereas the scratch was almost covered by cells in the negative control group and blank control group. The invasion assay showed that the number of A375?shRNA2 cells passing through the Transwell chamber was significantly smaller than that of A375 and A375?con cells(both P 0.05). Conclusion The silencing of SEMA5A gene by lentivirus?mediated shRNA could effectively down?regulate the expression of semaphorin 5A, and inhibit the growth, invasion and migration of A375 cells.
ABSTRACT
Nuclear proteins often form punctiform structures, but the precise mechanism for this process is unknown. As a preliminary study, we investigated the aggregation of an HSV-1 immediate-early protein,infected-cell protein 22 (ICP22), in the nucleus by observing the localization of ICP22-EGFP fusion protein.Results showed that, in high-level expression conditions, ICP22-EGFP gradually concentrates in the nucleus,persists throughout the cell cycle without disaggregation even in the cell division phase, and is finally distributed to daughter cells. We subsequently constructed a mammalian cell expression system, which had tetracyclinedependent transcriptional regulators. Consequently, the location of ICP22-EGFP in the nucleus changed with distinct induction conditions. This suggests that the cellular location of ICP22 is also influenced by promoter regulation, in addition to its own structure. Our findings provide new clues for the investigation of transcriptional regulation of viral genes. In addition, the non-protease reporter system we constructed could be utilized to evaluate the role of internal ribosome entry sites (IRES) on transcriptional regulation.
ABSTRACT
HSV-1 infection-mediated regulation of mRNA translation in host cells is a systematic and complicated process. Investigation of the details of this mechanism will facilitate understanding of biological variations in the viral replication process and host cells. In this study, a comparative proteomics technology platform was applied by two-dimension electrophoresis of HSV-1 infected normal human L-02 cell and control cell lysates. The observed protein spots were analyzed qualitatively and quantitatively by the PDQuest software package. A number of the different observed protein spots closely associated with cellular protein synthesis were identified by matrix-assisted laser-desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS). The expression levels of the RPLP1 protein, which is required for mRNA translation, and KHSRP protein, which is involved in rapid decay of mRNA, were up-regulated, whereas the expression level of RNP H2, which is involved in positive regulation on the mRNA splicing process, was down-regulated. All of these results suggest that HSV-1 infection can influence cellular protein synthesis via modulation of cellular regulatory proteins involved in RNA splicing, translation and decay, resulting in optimisation of viral protein synthesis when cellular protein synthesis is shut off. Although there is need for further investigations regarding the detailed mechanisms of cellular protein control, our studies provide new insight into the targeting of varied virus signaling pathways involved in host cellular protein synthesis.
ABSTRACT
The three immediate-early proteins of HSV-1, ICPO, ICP22, and ICP27, have specific and pivotal functions in transcriptional activation and inhibition, multiple regulatory and control processes of viral genes. In this paper, the expression and localization of these three proteins were studied in neuroblastoma cells using biochemical assays, and their possible and potential interactive functions are discussed. The data show that the three proteins are localized in different structures, specifically in the PML-NB-associated structure, which is a specific nuclear structure composed of many protein molecules and bound tightly to the nuclear matrix in neuroblastoma cells. The results suggest that the activating and suppressive functions of ICPs are mostly dependent on their transcriptional and regulatory roles, including the PML-NB-associated structure.
ABSTRACT
As an immediate-early protein of herpes simplex virus, infected-cell polypeptide 0 (ICP0) exhibits complicated interactions with host cells, and its regulatory function on gene expression is of great importance. Since the ICP0 encoding sequence contains many rare codons which are absent in E.coli, and ICP0 is highly unstable in prokaryotic cells, expression of entire ICP0 in prokaryotic cells has never been reported. In order to further investigate the function of ICP0, a recombinant plasmid was constructed by subcloning a cDNA fragment encoding an amino-terminal of 105 residues of the ICP0 protein into pGEX-5x-1 vector. The resulting GST-105 fusion antigen peptide was expressed with high efficiency in E.coli. Antibodies prepared after the immunization of mice with purified fusion protein can recognize not only the denatured ICP0 protein, but also the native ICP0 protein with normal biological conformation.
ABSTRACT
Herpes simplex virusⅠ(HSVⅠ) regulating the pathway of transcription and translation modify in host cell is a very systematic and complicate system. A clear understanding of the concrete mechanisms of infection will greatly help to comprehend the virus replication and the interaction with the host cell. By the analysis of 2-DE, the heterogeneous nuclear ribonucleoprotein H2 in human fetal liver cell represent distinction after the HSVⅠinfection.Utilization of Northern blot and Western blot technologies verified the expression of hnRNP H2 in different stage of virus infection is varied.