OVALBUMIN mRNA, COMPLEMENTARY DNA AND HORMONE REGULATION IN CHICK OVIDUCT

ABSTRACT Chick oviduct differentiation is controlled by various steroid hormones, including both oestrogen and progesterone. Administration of oestrogen to chicks results in differentiation of tubular gland cells, which synthesize differentiated cell products, including ovalbumin and conalbumin. Ovalbumin can constitute as much as 60% of the protein synthesized by oviduct in the fully stimulated chick. Methods have been developed that allow for the quantitative assay of ovalbumin mRNA, the specific isolation of ovalbumin synthesizing polysomes by use of immunologic techniques, as well as the synthesis of a DNA probe complementary to the ovalbumin mRNA. With these techniques we have found that the rate of ovalbumin synthesis is proportional to the content of ovalbumin mRNA. Hybridization studies using the DNA probe indicate that there are only two copies of the ovalbumin gene per genome, and that there is no amplification of the ovalbumin genes to account for the large amount of ovalbumin synthesized.