FIG. 6.

The UCS is required for N-glycosylation of MSG in insect cells. Insect cells were infected with recombinant baculoviruses containing genes encoding UCS-MSG (lanes 1 and 2), MSG (lanes 3 and 4), or SP-A, an unrelated protein (lanes 5 and 6). Lysates from uninfected cells are in lanes 7 and 8. The cells were incubated in the absence (−) or presence (+) of 5 μg of tunicamycin per ml for 24 h and harvested by scraping. Cell lysates were fractionated on a 6% Novex gel, transferred to nitrocellulose, and reacted with MAb RA-E7. The blot was developed by incubation with antimouse IgG horseradish peroxidase-labeled conjugate and horseradish peroxidase-dependent oxidation of o-phenylenediamine. The positions of Bio-Rad low-molecular-mass markers are indicated to the left of lane 1.