Ribonucleic acid synthesis in isolated mitochondria from Tetrahymena.

Some conditions of RNA synthesis in vitro in isolated mitochondria of Tetrahymena pyriformis were investigated. Sucrose gradient centrifugation analyses and methylated albumin-coated Kieselguhr column chromatography of the RNA synthesized in vitro demonstrate that RNA ranging from 14 S to 18 S, not transfer RNA, was synthesized. Furthermore, the RNA is hybridizable with mitochondrial DNA, and the hybridization is not inhibited by the addition of RNA isolated from the material sedimenting at 105,000 x g after centrifugation of mitochondrial lysate for l+ to 2 hours. Although net transfer RNA synthesis does not occur, the transfer RNA fraction was labeled if 3H-ATP was used for incorporation, suggesting that the incorporation is due to the addition of 3H-ATP at the terminus of the transfer RNA molecule.