Genetic Screens Of Regulators Involved In Cholesterol Metabolism In Mammalian Cells

Cholesterol is the principal sterol and it is an essential component of animal cell membranes. Abnormal cholesterol level leads to lots of diseases, such as atherosclerosis, which is the primary cause of heart disease and stroke; Additionally, Alzheimer's disease, obesity and diabetes are also thought to be related to cholesterol metabolism. Under normal conditions, the level of cholesterol is tightly controlled by a series of feedback systems. There are two known principal feedback pathways in cholesterol homeostasis. The first one is that the activity of HMG-CoA reductase (HMGCR), which is believed to be the rate-limiting enzyme in cholesterol biosynthesis, is regulated by sterol and nonsterol end-products through multiple mechanisms, among which the sterols-induced degradation of HMGCR is the most important one; another pathway involves the SREBP cleavage.To further study the molecular mechanism in cholesterol biosynthesis, we introduce lentivirus-based VBIM (Validation-Based Insertional Mutagenesis) insertional mutagenesis system as tools, and incorporate with somatic cell genetics to screen the novel regulators involved in cholesterol homeostasis. The results showed that we obtained several kinds of mutant cells that are deficient in cholesterol feedback regulation. Additionally, we also get some clones among which one or more new genes may be abnormal, which are being identified currently.