Regulation Of Interactin Between Ran And GlyRS On Milk Protein Synthesis In Dairy Cow Ma-mmary Epithelial Cells

The mechanisms of milk protein synthesis are important basis issue of life science. In recent years, some progresses on this research have been made. How the nucleus and cytoplasm reply the amino acid signal and regulate the milk protein synthesis? These questions are still the important scientific questions that are needed to be solved in lactation biology nowadays. Ran as an important cell growth factor plays roles in a variety of cellular activities, including DNA replication, the nucleus membrane reconstruction, spindle formation and material of nuclear plasma transport and so on. At present, there are few reports about the functions and interaction proteins of Ran in the process of development of dairy cow mammary. In this study, the dairy cow mammary epithelial cells of lactating were cultured in vitro. The regulation of Ran and the interaction between Ran and glycyl-t RNA synthetase(GlyRS) in the process of lactating of dairy cow mammary epithelial cells were studied. Basic data of the mechanism of regulation of lactation and development of animal mammary and the theory basis of the regulation of quality and quantity of milk were provided by this study.In this study, the breast tissue of Chinese Holstein cows was used for the culture of dairy cow mammary epithelial cells in vitro. For the detection of the purity of dairy cow mammary epithelial cells, the protein immunoblotting(WB) and immunofluorescence(IF) were used to detect the expression of cytokeratin 18(CK18) and ?-casein(CSN2) in the cells. The cell model of lactation was established by adding 0.6mmol/L of methionine in the medium and the expression of CSN2 and Ran in the lactation cell model was tested by WB. The result showed that compared with the control cells(culture in normal medium), the expression of CSN2 and Ran in lactation cell model was significant increased(p <0.01).The mammary epithelial cells of lactating dairy cow were cultured for the study. The interaction between Ran and GlyRS was tested by co-localization technique. The positively regulation of Ran and GlyRS in the process of lactating was tested by WB. For the Fluorescence resonance energy transfer(FRET) analysis, the recombinant plasmids Ran-RFP and GlyRS-GFP were constructed and co-transfected into the mammary epithelial cells. The result of FRET showed that there was a direct interaction between Ran and GlyRS.In summary, in the process of lactating in dairy cow mammary epithelial cells, Ran and GlyRS interact with each other and positively regulate the lactating.