MRNA Differential Display Analysis Of KAx-3Cells And RNAi-allC Cells In Dictystelium Discoideum

Dictyostelium discoideum belonging to the social amoeba reproduces by binary fission. In poor growth condition, it changes into multicellular development stages.Induced by chemotaxis cAMP, single cells aggregate together. And the construction of the multicellular structure goes through four stages:cell aggregation, cell mound, slugs and fruiting body. On the cell mound stage, cohesion moleculars like gp150, gp80, DdCAD-1make the single cells interacting with each other. Among them, gp150encoded by LagC gene plays an essential role in the cell development and differentiation. Related researchers in our lab that had studied the wide type cell KAx-3and the LagC gene knocked down munt cells AK127found that AK127cannot be able to complete the multicellular development and just stay in the basin shape condition. By the mRNA differential display analysis method, allantoicase gene was selected and its expression was very low in the mutant cell AK127. Allantoicase is an enzymes in purine metabolic pathway that can decomposite allantoic acid into NH3and CO2. There are studies showing that a certain concentration of NH3can be able to inhibit the cell outside cAMP concentration directely and cell aggretion indirectly.The researching materials in the thesis are Dictyostelium discoideum wild type cells KAx-3and mutant cells RNAi-allC with the silenced allantoicase gene that interfered by a carrier, pActl5Gal-allC. In the trophophase, there are obvious differences between KAx-3and RNAi-allC. Observed under microscopes, the size of KAx-3is bigger than that of RNAi-allC. Extracting the total RNA of KAx-3and RNAi-allC respectively and compareing their gene expression with the mRNA differential display method, we found a gene fragment that just expressed in the mutant type. And the nucleotide is given an accession number KC759140. With a special Zinc functional structure and Leukotriene-A4-Hydrolase C terminal, we conjectured that the protein encoded by the differential fragment is another homolog of Leukotriene-A4-Hydrolase in Dictyostelium discoideum.