Single-stranded RNA as primers of terminal deoxynucleotidyl transferase for template-independent DNA polymerization

Terminal deoxynucleotidyl transferase (TdT) has been characterized as template-independent polymerase using single-stranded DNA (ssDNA) as primers to generate random oligonucleotides. However, the extension performance of TdT to single-stranded RNA (ssRNA) is vague. By systematically comparing and contrasting the performance of TdT-catalyzed ssDNA and ssRNA extension, it is indicated that the catalytic efficiency of ssRNA as primers was about 3 times lower than ssDNA as primers. Collectively, it is believed that understanding the catalytic performance of TdT will help to design the strategy to synthesize chimeric DNA on 3′-OH of ssRNA, which becomes invaluable.