IMMORTALIZED GASTRIC EPITHELIAL-CELL LINE GSM06 SYNTHESIZES HYALURONAN UNDER THE INFLUENCE OF SIMIAN-VIRUS-40 LARGE T-ANTIGEN EXPRESSION

GSM06 is a cell line established from the stomach of transgenic mouse harboring a temperature-sensitive simian virus 40 (SV40) large T-antig en gene, H-3-labeled macromolecules produced by the cells incubated wi th [H-3] glucosamine were characterized to examine whether or not GSM0 6 cells synthesize mucin (mucus glycoprotein), The GSM06 cells grew un til a confluent monolayer formed at 33 degrees C (the permissive tempe rature for SV40 large T-antigen expression), and the H-3-labeled macro molecules appeared in both cell extract and medium during culture for at least 1 week, Unexpectedly, almost all H-3-labeled macromolecules, which were excluded from a column of Sepharose CL-4B, were identified as hyaluronan by analyses using Sepharose CL-BB chromatography, cesium trifluoroacetate equilibrium centrifugation, treatment with dithiothr eitol, and trypsin, hyaluronidase, and chondroitinase ABC digestion. A t a nonpermissive temperature (39 degrees C), GSM06 cells grew only sl ightly, but produced much more hyaluronan than at 33 degrees C, The re sults indicate that GSM06 cells produce not mucin, but hyaluronan, and that the expression of large T-antigen may influence hyaluronan synth esis in GSM06 cells.