Leonard TB, Jacob ST. Differential effects of cordycepin triphosphate and 9 beta-D-arabinofuranosyladenine triphosphate on tRNA and 5 S RNA synthesis in isolated nuclei.
BIOCHIMICA ET BIOPHYSICA ACTA 1979;
563:150-4. [PMID:
497205 DOI:
10.1016/0005-2787(79)90015-7]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although cordycepin 5'-triphosphate (3'-dATP), at low concentrations, preferentially inhibits chromatin-associated poly(A) synthesis in isolated nuclei, higher levels of the inhibitor prevent both rRNA (RNA polymerase I activity) and hnRNA (RNA polymerase II activity) synthesis in vitro (Rose, K.M., Bell, L.E. and Jacob, S.T. (1977) Nature 267, 178-180). The present studies demonstrate that this nucleotide can also inhibit tRNA and 5 S RNA synthesis (RNA polymerase III activity). At 50-200 microgram/ml, 3'-dATP inhibits incorporation of [3H]UTP into tRNA and 5 S RNA by approximately 65%, whereas the syntheses of these RNAs were completely blocked when [3H]GTP was used as the substrate. These data suggest the formation of poly(U) in the tRNA and 5 S RNA regions, which is resistant to 3'-dATP. In contrast, another ATP analog, Ara-ATP, which selectively inhibits poly(A) synthesis, does not block tRNA and 5 S RNA synthesis in isolated nuclei. The production of these RNA species in isolated nuclei is also insensitive to Ara-CTP and 2'-dATP. These data suggest that 3'-dATP exerts general inhibitory effects on RNA synthesis and further substantiate the conclusion that Ara-ATP is a selective inhibitor of the polyadenylation reaction in vitro.
Collapse