Metabolism of polyadenylated mRNA in growing human lymphocytes.
The kinetics of degradation of newly synthesized, cytoplasmic polyadenylated RNA have been examined in normal human lymphocytes stimulated to grow with phytohemagglutinin. A single class of poly(A)-bearing RNA was identified with a half-life of approximately 50 h. In the presence of actinomycin D, the half-life was 5 to 6 h, and virtually no decay of pulse-labeled material was detectable after 6 h of chase incubation with cordycepin. These findings contrast sharply with data obtained from other growing human cells used as controls: polyadenylated mRNA in MOLT-4 cells, a cultured line of T lymphocytes, had a half-life of 2 h in the presence of actinomycin D. The stability of poly(A)-containing RNA in stimulated lymphocytes from normal donors is therefore not simply a manifestation of cell proliferation. In normal resting lymphocytes, Berger and Copper [(1975) Proc. Natl. Acad. Sci. U.S. 72, 3873--3877] reported the existence of 2 classes of polyadenylated mRNA with half-lives of under an hour and greater than 20 h, respectively. Since short-lived poly(A)-bearing mRNA is absent from mitogen-stimulated lymphocytes, the data suggest that stabilization of previously labile poly(A)-bearing RNA is one of many carefully regulated processes accompanying growth induction in normal lymphoid cells.
D002453:Cell Cycle; D003593:Cytoplasm / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D003839:Deoxyadenosines / Q000494:pharmacology; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011061:Poly A / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism; D014529:Uridine / Q000378:metabolism
D003839:Deoxyadenosines; D010835:Phytohemagglutinins; D012333:RNA, Messenger; D003609:Dactinomycin; D011061:Poly A; D012313:RNA; D014529:Uridine