Open AccessStudies on the Synthesis of Casein Messenger RNA during Pregnancy in the Rabbit
Author(s) -
SHUSTER Robert C.,
HOUDEBINE LouisMarie,
GAYE Pierre
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb11106.x
Subject(s) - casein , messenger rna , reticulocyte , biology , polysome , rna , mammary gland , lactation , protein biosynthesis , in situ hybridization , transcription (linguistics) , microbiology and biotechnology , medicine , endocrinology , biochemistry , gene , pregnancy , ribosome , genetics , linguistics , philosophy , cancer , breast cancer
The quantity of casein mRNA in the rabbit mammary gland was assayed during the course of pregnancy, by translation of casein mRNA in a reticulocyte lysate and by hybridization to DNA complementary to purified casein mRNA. Both methods indicated that the major increases in the concentration of casein mRNA in both polysomal and total cellular RNA occurred between the 18th and 25th day of pregnancy. The change in casein mRNA concentration during this period coincided with a sharp rise in casein synthesis in mammary gland explants suggesting that the levels of casein mRNA determine the rate of casein synthesis in the mammary gland. The sensitivity of the hybridization assay made it possible to detect the presence of casein mRNA in virgin animals and during the very early stages of pregnancy. At day 5, casein mRNA was found associated with polysomes indicating that there was probably some casein synthesis at this early stage of gestation. These results suggest that the hormones controlling lactogenesis in the rabbit may function by augmenting the rate of casein mRNA synthesis rather than initiating transcription of previously inactive genes.