Antibody Nucleic Acid Complexes. Immunospecific Retention of N⁶-Methyladenosine-Containing Transfer Ribonucleic Acid†

Antibodies specific for N⁶-methyladenosine (m⁶A) were immobilized on Sepharose and the resulting immunoadsorbent was tested for its ability to retain those Escherichia coli tRNAs containing the antigenic hapten, i.e., m⁶A. Results obtained with [³²P]PO₄- and [methyl-³H]-methionine-labeled tRNAs indicated that approximately 3 to 5% of the radioactive RNA was retained by the immunoadsorbent. Under identical conditions, but in the presence of m⁶A (1 mg/mL), less than 0.2% of the radioactivity was retained. Subsequent characterization of the retained tRNA via (a) analysis of wethyl-³H-labeled, methylated nucleosides, (b) two-dimensional gel electrophoresis, and (c) analysis of the retention of [³H]aminoacyl-tRNA species led to the conclusion that the anti-m⁶A/Sepharose adsorbent quantitatively and exclusively retained a single tRNA species containing m⁶A, namely, tRNA^Val.