Ovalbumin Messenger RNA: Evidence That the Initial Product of Transcription Is the Same Size as Polysomal Ovalbumin Messenger

Abstract

Ovalbumin mRNA, the major secretory protein of the chick oviduct, appears not to be made as a high-MW precursor when artifacts due to aggregation are eliminated. No ovalbumin mRNA sequences that will hybridize to complementary DNA made against ovalbumin mRNA are found in concentrated samples of hen oviduct RNA larger than 28 S. The sensitivity of the hybridization assay is sufficient to detect less than 1 molecule of ovalbumin mRNA precursor per tubular gland cell. Newly synthesized ovalbumin mRNA isolated from immature chicks stimulated briefly by estrogen is the same size as that found in hen polyribosomes. Ovalbumin mRNA probably does not undergo any significant change in MW from its initial transcription to its incorporation into polyribosomes.