Research Of Cytochrome C Gene Expression During Apoptosis Of Dictyostelium Discoideum

Dictyostelium discoideum is a simple unicellular eucaryon which feeds on bacteria.It looks like amboe and is also called "social amboe".It lives in state of single cell with adequate food;but It develops in state of multicells with the lack of food.Its development goes through:four stages Aggregation, Mound,Slug and Fruiting body, and terminal form-Fruigitng body consists of stalk cells and spore cells. Spore cells are able to regrow in culture medium and relive in new cell cycles. Stalk cells are dead, as demonstrated by their inability to regrow in culture medium.Apoptosis is an active death process for better life,related to activation,expression and regulation of collection of genes in organisim,and is different from necrocytosis. In apoptosis, physiological and biochemical characters of cytomembrane and organelles are converted distinctly. Regulation mechanism of apoptosis is vague,which devided into two pathways:Extrinsic pathway(Death receptor pathway) and intrinsic pathway(Mitochondrial and endoplasmic reticulum pathways). Cytochrome c is a key carrier in respiratory chain and plays an important part in energy metabolism.On the other hand, cytochrome c is a vital factor of signal transduction of mitochondria pathway in apoptosis,which activates signal pathway involved by caspases,and caused apoptosis finally.Function of cytochrome c in signal pathway of apoptosis is researched in some species,but it is rarely reported in Dictyostelium discoideum.Expression and regulation mechanism of cytochrome c in apoptosis of Dictyostelium discoideum is indistinct currently.Dictyostelium discoideum is an important model for the investigation of problems that are relevant to development and pathogenesis.In this article, morphological characteristics of wild-type Dictyostelium discoideum at multicellular developmental phase are observed and the expression of cytochrome c gene in prestalk cells and prespore cells of wild-type Dictyostelium discoideum at developmental phase of 16h,18h,20h is detected by Western blot and Fluorescence Quantitative PCR.and then we researched cytochrome c gene's function in apoptosis of Dictyostelium discoideum.The result of Western blot thowes that the content of cytochrome c gradually increases in apoptosis of prestalk cells of Dictyostelium discoideum and gets to top during the phase of 20h; the content of cytochrome c is stable in developmental process of prespore cells of Dictyostelium discoideum and its expression variation is stable; The result of Fluorescence Quantitative PCR showes that the expression of cytochrome c gene in prestalk cells of Dictyostelium discoideum takes on a increasing trend and is apparently higher than it in prespore cells of Dictyostelium discoideum,extremely similar with the result of Western blot.Conclusions:Two confirmed results indicate that cytochrome c,in some extent, participate in the apoptosis of Dictyostelium prestalk cell. The expression of cytochrome c gene in apoptosis of Dictyostelium discoideum obviously increases and its expression tendency is gradually rising.It indicates that cytochrome c is closely relevant with occurrence of apoptosis of Dictyostelium discoideum, and it plays an important role in apoptosis.