Synthesis and secretion of ovalbumin by mouse-growing oocytes following microinjection of chick ovalbumin mRNA.

Mouse-growing oocytes were injected with chick ovalbumin mRNA. The oocytes were cultured for 18 h in the presence of [3H]leucine and the labeled ovalbumin was measured by immunoprecipitation. Two types of ovalbumin were precipitated by antibody to ovalbumin; one co-migrated with authentic, glycosylated ovalbumin in an 18% polyacrylamide gel and was estimated to be 45 000 D, whereas the other migrated faster with an apparent MW of 41 500 D. Both types of ovalbumin were also detected in the culture medium. This study demonstrates that mouse-growing oocytes can translate exogenous mRNA coding for a secreted protein and secrete two forms of the product.