In vivo repair of the 3'terminus of transfer RNA injected into amphibian oocytes.

Yeast transfer RNA specific for phenylalanine has been treated chemically to remove either one or two nucleotides of its 3' terminus and has been injected into Xenopus laevis oocytes to test whether this RNA can be repaired in vivo. The results obtained showed that oocytes could aminoacylate and thus repair tRNAPhe that has lost both its terminal adenosine and 3' phosphate. A similar result was obtained with tRNAPhe that had undergone two full cycles of 3' terminal nucleotide removal. The oocytes cannot aminoacylate tRNAPhe whose 3' terminal ribose has been oxidized with periodate or the derivative that retains a 3' phosphate after adenosine removal. In vitro assays show that the Xenopus ovary contains a tRNA nucleotidyl transferase with the properties similar to enzymes obtained from other sources which may be responsible for the 3' terminal repair observed in vitro.