title: High-molecular-weight nuclear polyadenylate-containing ribonucleic acid isolated from the lactating guniea-pig mammary gland contains milk-protein messenger ribonucleic acid sequences.
abstract: 1. Steady-state poly(A)-containing nuclear RNA was isolated from the lactating guinea-pig mammary gland and analysed by sucrose-gradient centrifugation under denaturing conditions. 2. Nucleic acid-hybridization studies demonstrated the presence of small amounts of high-molecular-weight RNA species containing milk-protein mRNA sequences sedimenting at 25S. These were not found in the post-nuclear supernatant, where milk-protein sequences sedimented only between 12S and 15S; these were also the predominant species in the nuclear fraction. 3. The results are consistent with the transcription of milk-protein genes as high-molecular-weight precursor RNA species, 3-4 times as large as the active mRNA species isolated from the post-nuclear fraction.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000032:analysis; D005260:Female; D006168:Guinea Pigs; D007774:Lactation; D008321:Mammary Glands, Animal / Q000032:analysis*; D008894:Milk Proteins / Q000235:genetics; D008970:Molecular Weight; D011061:Poly A; D011247:Pregnancy; D012313:RNA / Q000235:genetics / Q000302:isolation & purification*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D008894:Milk Proteins; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA