Intracellular Compartmentation and Secretion of Carp Proinsulin Synthesized in Xenopus Oocytes

Abstract

Carp proinsulin and rabbit globin, synthesized in Xenopus oocytes in response to simultaneously injected mRNA, are found in membrane vesicles and in the cytosol, respectively. After 24 h of incubation labeled proinsulin, but not globin, is found also in the medium, indicating specific secretion from the oocytes. No insulin could be found either within or outside the oocytes. The mRNA for a given protein evidently contains the information for its intracellular destination and its eventual secretion.