Intranuclear location of the tRNA splicing enzymes.

The intracellular location of the enzymes that excise tRNA intervening sequences and subsequently religate the molecular was investigated in Xenopus oocytes. All the splicing activity detected in a whole oocyte was present in the nucleus. By manual separation of the nuclear envelope and the nuclear contents (which form a gel-like structure in the presence of Mg++) it was found that all the activity of both splicing enzymes was located in the nuclear contents and was not associated with the nuclear membrane.