title: The nucleotide sequence of two bovine lens phenylalanine tRNAs. Possible activation of a new phenylalanine tRNA gene during differentiation of lens cells.
abstract: Bovine lens fiber cells contain two major isoacceptors of phenylalanine tRNA, tRNA1Phe and tRNA2Phe whereas lens epithelial cells contain mainly tRNA2Phe (Ortwerth, B.J,, Yonuschot, G.R., Heidlege, J.F., Chu-Der, O.M.Y., Juarez, D., and Hedgcoth, C. (1975) Exp. Eye Res. 20, 417-426). Thus, the induction of a new species of tRNAPhe accompanies the differentiation of lens cells in vivo. These two species of tRNAPhe have been purified and their sequences have been analyzed. The results of the analyses show that the sequence of tRNA2Phe is identical with beef liver tRNAPhe while tRNA1Phe differs from tRNA2Phe by a guanosine to adenosine substitution at position 57. Therefore, the T psi CG sequence in the ribosylthymine loop of tRNA2Phe is replaced by T psi CA in tRNA1Phe, This observation demonstrates a case in which a change in sequence of tRNA isoacceptors accompanies cell development rather than changes in the level of post-transcriptional modification as noted in other systems (reviewed by Osterman L.A. (1979) Biochimie (Paris) 61, 323-342). The conversion of guanosine to adenosine in the ribosylthymine loop of lens tRNA1Phe suggests a possible activation of a new tRNAPhe gene during the differentiation of lens cells, although the possibility that this replacement may be catalyzed by a transglycosylase type enzyme has not been ruled out.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D007908:Lens, Crystalline / Q000032:analysis*; D009711:Nucleotides / Q000032:analysis*; D009841:Oligonucleotides / Q000032:analysis; D010649:Phenylalanine / Q000032:analysis; D011116:Polynucleotide 5'-Hydroxyl-Kinase / Q000378:metabolism; D012343:RNA, Transfer / Q000032:analysis* / Q000235:genetics; D012260:Ribonucleases / Q000378:metabolism
chemical_list: D009711:Nucleotides; D009841:Oligonucleotides; D010649:Phenylalanine; D012343:RNA, Transfer; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D012260:Ribonucleases