FIGURE 8.

A truncated Tg containing the first four type-1 repeats is secreted rapidly and independently of ChEL. Above the data, the schematic diagram shows the construct(s) used in this figure. In the experiment, 293 cells were transiently transfected to express either empty vector (Con) or Tg-A340X ± secretory ChEL. The cells were then pulse-labeled for 30 min with ³⁵S-amino acids and chased in complete medium for 1 h. At that time, cell lysates (C) and media (M) were collected before immunoprecipitation with anti-Tg and analysis by SDS-PAGE under nonreducing (left panel) or reducing (right panel) conditions. Note that for Tg-A340X, disulfide oxidation (as measured by mobility difference between reduced and nonreduced gel bands), glycosylation of secreted protein, and extent of secretion were unaffected by the presence of the ChEL domain. The positions of molecular mass marker proteins are shown.