The Expression Of ORC1 Gene During Proliferative Process Of Vascular Smooth Cells In Rats

Background:Atherosclerosis and its cardiovascular complication continue to be a major health problem globally. The situation is becoming alarming due to the lack of an effective preventive measure for restenosis after angioplasty and increasing incidences. The abnormal growth of vascular smooth muscle cells (VSMCs) is a prominent feature of vascular disease, including atherosclerosis and restenosis after angioplasty.In general, the progression of the cell cycle is a complex, stepwise process involving resting G0 phase, and cell growth involving G1, S and G2/M phase. In arterial media, VSMCs are normally quiescent, proliferate at low indices (<0.05%), and remain in the G0/G1 phase of the cell cycle. After vessel injury, VSMCs migrate to the intimal layer of the arterial wall, where they exit from their quiescent state and reenter the cell cycle.DNA replication takes place in two continuous phases: initiation and elongation, most of the recent works on human tumor cell line DNA replication has been focused on identification and characterization of key components of DNA replication elongation factors like proliferating cell nuclear antigen (PCNA), DNA polymeraseα, DNA polymeraseδ, and replication protein A. However, there is no detailed study regarding the initiation of DNA replication that is the rate-determining step in DNA replication. DNA replication in eukaryotes is initiated at discrete sites on chromosome through the coordinated action of a number of replication initiation factors, this process is best understood in yeast Saccharomyces cerevisiae, where a six protein origin recognition complex (ORC) binds to specific DNA sequences near the origin of replication and recruits other replication initiation factors like cdc6, cyclin-dependent kinase 1 (cdk1) and MCM2-7 to form the pre-replication complex (Pre-RC). Activation of cdks results in the recruitment of elongation factors like cdc4-5, DNA replication polymerase and RPA to the Pre-RC at the replication origin. Origin recognition complex-1 (ORC1) is one of the largest sub-units of ORC. Therefore, the investigation of ORC1 gene could provide an important insight into...