Correlational Study On Allanoicase And Gp150during Dictysotelium Discoideum Development

Dictyostelium discoideum is a lower eukaryotic protozoan which forms gregarious life. Of course, Dictyostelium discoideum is considered as a good material for study of signal transduction and cell development.Gp150is a heterophilic adhesion molecule and is encoded by lagC gene. It plays an important role on the development of Dictyostelium discoideum. It had been proved that gp150handled the formation of stalk cells. Allantoicase gene was found when we study the function of gp150and it played an important role in Dictyostelium discoideum. However, how they internet with each other in the complexity regulation network, has not been reported.In order to confirm that all the above, we choosed KAx-3cells that developed to16h with allantoicase antibody through Co-Immunoprecipitation technology to probe the proteins contacts with allantoicase.40S ribosomal protein S3(rpS3) and40S ribosomal protein S16(rpS16) were found in the experiment. In our laboratory, it had been found that gp150also interacted with rpS3. Initially, rpS3was considered as a subunit of ribosome. As research progressed, rpS3proteins also possess a variety of adjustment and can induce programmed cell death, as well as participate in cells repair, and so on. We suppose that the three proteins may have some relationships to regulate the multicellular development together. Of course, the conjecture need to be further confirmed.We tested the expression of allantoicase, gp150and rpS3respectively which both in the24h development of wild-type KAx-3cells and RNAi-allC cells by western-blot technology. During the development of KAx-3cells, the expression of allantoicase changed during different stages. It remained a lower level from Oh to8h (Aggregation), then increased from8h to16h (Mound and Slug), and then significantly lower from16h to24h (Fruiting body). Gp150started expression at8h and the following trends were similar to allantoicase. rpS3declined gradually with time, highest at Oh and lowest at20h, its downward trends was more obvious during Mound and Slug. We also are surprised to find that the three proteins were all almost no expression in RNAi-allC mutations. Overall, both allantoicase and gp150have a higher level expression during the critical stages. On the other hand, rpS3declined remarkably in key stages. The finally development of KAx-3would form two types of cells:stalk cells (dead cells) and prespore. Gp150has been found to regulate the formation of stalk cells. To sum up, our reserches and previous reports maybe reveal that the three proteins are all related closely to the development of discoideum, especially in the development of stalk cells. It is possibly that gp150initiates cell differentiation firstly, then allantoicase as its downstream gene, may affect the phosphorylation of rpS3indirectly by ammonia, and then rpS3phosphorylated mobilizes from cytoplasm to nucleus to influence cell differentiation and multicellular development. It need to a further study as to whether allantoicase can regulate closely to formation of the stalk cells likes gp150. We continue to study allantoicase due to its changes are similar to gp150during the key stages. Gp150has been found to regulate the formation of stalk cells, so we select KAx-3strains which develop to16h and18h, and their prestalk cells and prespore cells were separated to research allantoicase by immunofluorescent technique respectively. We found that the fluorescence in prestalk section was much light than in prespore which was consistent with gp150. The results suggest that allantoicase may take part in the formation of stalk cells. To further confirm the speculation above, we quantified allantoicase from mRNA level by real-time PCR and the data was consistent of immunofluorescent technique. Two kind experimental results indicate that gp150and allantoicase may regulate the formation of stalk cells by rPS3. The specific relationship among the three proteins is subject to further study.