Synthesis of messenger RNA-like molecules in isolated myeloma nuclei

• Published in: Nucleic acids research 1977-06, Vol.4 (6), p.1739-1758
• Main Authors: Mory, Yves Y., Getter, Malcolm L.
• Format: Article
• Language: English
• Subjects: Amanitins - pharmacology; Animals; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Cells, Cultured; Cytoplasm; Guanosine Triphosphate - metabolism; Kinetics; Mice; Molecular Weight; Multiple Myeloma - metabolism; Poly A - metabolism; Polyribosomes - metabolism; Reticulocytes - metabolism; Ribonucleases; RNA, Messenger - biosynthesis; RNA, Neoplasm - biosynthesis; Uridine - metabolism
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/4.6.1739

Nuclei isolated from mouse myeloma cells grown in tissue culture are capable of synthesizing RNA for prolonged periods of time. Addition of cytoplasmic extracts to the system stimulates slightly the rate and prolongs the time of synthesis. As judged by sedimentation in SDS and in formamide gradients, the size of the RNA synthesized is heterogeneous from smaller than 10S to larger than 45S, thus resembling in vivo made RNA. The characteristics of some of the RNA are in keeping with those expected to be for mRNA. Fifty percent of the RNA synthesis is sensitive to α-amanitin. After an incubation of two hours in the absence of a-amanitin about 10 percent of the newly synthesized RNA is found outside of the nuclei; it sediments with a broad distribution at 18S. A considerable fraction of the RNA that is released from nuclei in vitro can promote the formation of polyribosomes, and contains molecules that are polyadeny-lated and “capped”.