| Background:The vascular smooth muscle cell (VSMC) is well known to be one of the important components of the vessel wall. The excess proliferation of VSMC is the common pathologic basis for artherosclerosis, hypertension and restenosis. RNA interfering is a new method for researching the function of gene and committing gene therapy, which can inhibit the expression of target gene specially and effectively. Origin recognition complex (ORC) is composed of six subunits, which can specially bind to the replication origin in the genomes. It was first detected in Saccharomyces cerevisia, and then detected in various cells. Cell can't process the DNA replication without ORC. After binding to the replication origin, ORC provide a pad for the other initiation factors (such as cdc6, Cdt1, MCM2-7) to conform the pre-replicative complex (pre-RC). Activated by various kinase, pre-RC will promote the cell from G1-phase into S-phase and commence the DNA replication. The initiation of DNA replication is regulated by ORC activity in eucaryotic cell. All of ORC subunits bind to the DNA throughout the cell cycle in yeast, while in mammalian cells, the ORC2-6 subunits bind to the DNA, ORC1 is removed from the chromatin as cells progressed into S phase and rebound to chromatin only as cells progressed into late telophase. In eukaryotic cell,ORC1 accumulates in G1 and is degraded in S phase, but other ORC subunits remain at almost constant levels. It was defined"the ORC1 cycle". Therefore, It is a widely accepted opinion that ORC1 is the key to regulate the activity of ORC. We hypothesize that if the expression of ORC1 is repressed, the proliferation of VSMC will be inhibited.Objective: The purpose of present study is as follows:1) To pick out one pair of siRNA that is the best effective to inhibit the expression of ORC1 from three pairs of siRNAs.2) To explore the change of proliferative ability, after the VSMC is transfected with... |
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