Figure 6.

Biosynthesis of mature insulin secretory granules is not detectably affected by induced expression of Syn6t. (A) Syn 6t-10 cells either uninduced (-) or induced for 24 h with ponasterone (+) were pulse labeled, chased, and stimulated with secretagogue as described in the text. Proinsulin (Proins) and insulin (Ins) were recovered by immunoprecipitation with an anti-insulin antibody followed by SDS-PAGE and fluorography. (B) The cells as described below each panel were processed for electron microscopy as described in MATERIALS AND METHODS. A portion of the nucleus of the cell is oriented to the left of each image. The cells show relatively abundant secretory granules and mitochondria.