BIOCHEMICAL-BASES IN DIFFERENTIATION OF A MOUSE-CELL LINE GSM06 TO GASTRIC SURFACE CELLS

A mouse gastric surface cell line GSM06 established from a transgenic mouse harboring temperature-sensitive simian virus 40 large T-antigen gene was subjected to the lipid and glycoprotein analysis. When GSM06 cells were cultured for a long time after formation of a confluent mon olayer, they differentiated to resemble foveolar epithelial cells morp hologically. Biochemical changes during culture were studied in cells harvested just when a monolayer had formed (day 0), on day 7, and on d ay 21. Content of total phospholipids, cholesterol, cholesterol sulfat e, total sugar and sialic acid increased about 1.5-fold from day 0 to 7 and remained elevated till day 21. The fatty acid composition of pho spholipids revealed increased relative levels of oleic acid in phospha tidylcholine and phosphatidylethanolamine, and an increased level of p lasmenylethanolamine from day 0 to 7. The level of dolichylphosphate c ontinued to increase in a time-dependent manner. Glycosylation of vari ous proteins, detected with lectins, was enhanced from day 7. In addit ion, greater resistance to taurodeoxycholate and acetylsalicylic acid was observed on days 7 and 21 than on day 0. Thus, enhanced glycosylat ion of proteins and an overall increase in the area of cellular membra nes were the major changes in GSM06 cells during culture, and they wer e accompanied by an enhancement of cytoprotective potential.