Non-parallel kinetics and the role of tissue-specific factors in the secretion of chicken ovalbumin and lysozyme from Xenopus oocytes

Ovalbumin and lysozyme made in Xenopus oocytes under the direction of injected chicken oviduct messenger RNA accumulate at different rates in the surrounding culture medium. Pulse-chase experiments confirm that the intrinsic rate of lysozyme secretion from oocytes is 12 times that of ovalbumin. This slower rate of ovalbumin export is maintained following injection of either diluted oviduct RNA or purified ovalbumin messenger, the latter having been obtained by hybridization to cloned ovalbumin complementary DNA. These results suggest that the differential rates of transport observed in oocytes are not the consequence of competition for amphibian or avian factors and show that oviduct-specific proteins are not required for ovalbumin secretion.