News Release

Primordial RNA and origins of life

Peer-Reviewed Publication

Proceedings of the National Academy of Sciences

Researchers report a plausible primordial version of RNA that could have served as an early genetic polymer. RNA is believed to have played both genetic and catalytic roles early in the evolution of life, but the origins of RNA and its precursors remain uncertain. Further, prebiotic synthesis of adenine and guanine, two of the canonical nucleobases that make up RNA, remains challenging. Jack W. Szostak and colleagues tested whether the 8-oxo-purines, which could plausibly be synthesized prebiotically, and inosine could replace adenine or guanine in a functional RNA molecule. Activated 8-oxo-purine nucleotides were incorporated into a growing RNA strand at a much slower rate than the canonical nucleotides. Once incorporated, the 8-oxo-purines significantly slowed the incorporation of the next nucleotide. The presence of 8-oxo-purines in the template strand resulted in high copying error rates compared with the canonical nucleotides. By contrast, activated inosine nucleotides were incorporated at rates comparable to those of canonical nucleotides and exhibited specificity for forming base pairs with cytosine comparable to that of guanine. Incorporation of inosine into the strand had a minimal impact on the rate of incorporation of subsequent nucleotides. The results suggest that inosine could have substituted for guanine in an early version of RNA-based life, according to the authors.

Article #18-14367: "Inosine, but none of the 8-oxo-purines, is a plausible component of a primordial version of RNA," by Seohyun Kim, Derek O'Flaherty, Lijun Zhou, Victor Lelyveld, and Jack W. Szostak.

MEDIA CONTACT: Jack W. Szostak, Massachusetts General Hospital, Boston, MA; e-mail: szostak@molbio.mgh.harvard.edu

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