Chromatographic analysis of the aminoacyl-trnas which are required for translation of codons at and around the ribosomal frameshift sites of HIV, HTLV-1, and BLV

An examination of the frameshift signals or proposed signals within published sequences of retroviruses and other genetic elements from higher animals shows that each site utilizes a tRNA which normally contains Wybutoxine (Wye) base or Queuine (Q) base in the anticodon loop. We find experimentally that most of the Phe-tRNA present in HIV-1 infected cells lacks the highly modified Wye base in its anticodon loop and most of the Asn-tRNA in HTLV-1 and BLV infected cells lacks the highly modified Q base in its anticodon loop. Interestingly, Phe-tRNA translates a UUU codon within the ribosomal frameshift signal in HIV and Asn-tRNA translates a AAC codon within the proposed frameshift signals in HTLV-1 and BLV. Thus, the lack of a highly modified base in the anticodon loop of tRNAs in retroviral infected cells is correlated with the participation of these undermodified tRNAs in the corresponding frameshift event. This suggests that the “shifty” tRNAs proposed by Jacks et al. (Cell 55, 447–458, 1988) to carry out frameshifting may be hypomodified isoacceptors.