Synthesis of poly(A)-associated RNA in the prereplicative phase of isoproterenol-stimulated DNA synthesis.
Rapidly labelled RNA containing poly(A) sequences has been isolated from polysomes of mouse parotid glands. Filtration on Millipore and binding to poly(u) immobilized on Sepharose-4B, together with significant RNase-resistance (11-16%) indicated that this polysomal fraction contains large tracts of polyadenylate sequences. A single injection of isoproterenol, a procedure that causes, after a lag period of 20 hrs, a marked stimulation of DNA synthesis and cell division in salivary glands of rodents, induces a biphasic increase in the incorporation of (3H)-adenosine into poly(A)-associated polysomal RNA. The incorporation of (3H)-adenosine is already increased within 1 hour after stimulation, decreases at 3 hrs and increases again at 8 hrs, parallelling previously reported changes on chromatin template activity of mouse parotids. However, the percent poly(A) content, and the size of the poly(A)-associated RNA remain constant. Actinomycin D given 30 min prior to isoproterenol, inhibits isoproterenol-Stimulated poly(A)-rich RNA synthesis. These results demonstrate that, as part of the early molecular events of its action, isoproterenol regulates transcription of adenylate-rich RNA in mouse parotid gland.
D000818:Animals; D001665:Binding Sites; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis*; D004261:DNA Replication / Q000187:drug effects*; D003609:Dactinomycin / Q000494:pharmacology; D007278:Injections, Spinal; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008854:Microscopy, Electron; D010306:Parotid Gland / Q000187:drug effects; D011132:Polyribosomes / Q000378:metabolism; D012313:RNA / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D013268:Stimulation, Chemical
D012333:RNA, Messenger; D012335:RNA, Ribosomal; D003609:Dactinomycin; D012313:RNA; D004247:DNA; D012260:Ribonucleases; D007545:Isoproterenol