Viral RNA Strategy Triples mRNA Lifespan, Offering Path to Longer-Lasting Therapeutics
Key Insights
Researchers identified 23 viral RNA regulatory elements, termed "tailons," that enhance mRNA stability by exploiting host RNA tailing enzymes.
A newly discovered element, Pt1 (search), recruits poly(A) polymerase to re-extend shortened poly(A) tails, nearly tripling mRNA half-life from 7.6 to 23.1 hours.
Attaching Pt1 (search) to linear mRNA increased poly(A) tail length from 60 to up to 194 adenine bases, achieving stability comparable to circular RNA.
A research team in South Korea has developed a technology that extends the lifespan of messenger RNA (mRNA) (search) by approximately threefold by borrowing an RNA-protection strategy that viruses have refined over long evolutionary processes. The approach could significantly improve the stability of linear mRNA—which is relatively easy to manufacture—and may be used to increase the duration of efficacy for mRNA vaccines and therapeutics.
The work was led by Kim V. Narry, director of the RNA Research Center at the Institute for Basic Science (IBS) (search) and distinguished professor at Seoul National University's School of Biological Sciences. The team conducted a large-scale analysis of 337 virus species that infect vertebrates, uncovering regulatory elements that enhance RNA stability and protein production and elucidating their underlying mechanisms. The findings were published in the international journal Cell.
The Challenge of mRNA Instability
mRNA acts as a blueprint in the process of converting genetic information into proteins. At the end of mRNA, a sequence known as a poly(A) tail—comprising a continuous chain of adenine (A) bases—serves as a protective feature; when this poly(A) tail shortens, mRNA is easily degraded. To survive within host cells, viruses have evolved strategies to protect this tail by utilizing the host's RNA-regulating enzymes.
mRNA is inherently unstable at the molecular level and degrades rapidly in the body. Moderna, the company behind the mRNA COVID-19 vaccine, acknowledged in a report filed with the U.S. Securities and Exchange Commission that "the human body contains many enzymes that degrade RNA, making broad in vivo delivery difficult." The U.S. Food and Drug Administration has likewise pointed to RNA's intrinsic instability as a core challenge that RNA therapeutics must overcome.
Uncovering Viral "Tailons"
The research team focused on viral survival strategies. They divided the genomes of 337 virus species across 297 genera that infect vertebrates into approximately 200,000 RNA fragments, synthesized them, and conducted massively parallel analysis to identify RNA regulatory elements.
This led to the discovery of 23 regulatory elements that suppress degradation by creating a "mixed tail" at the RNA end, utilizing a host enzyme called TENT4 (search). These elements were distributed across 19 virus genera and classified into at least six types based on their sequences and structures. This indicates that evolutionarily distant viruses have developed independent strategies that utilize the same host RNA regulatory systems. The team named these viral RNA regulatory elements "tailons."
Pt1: A Novel Mechanism for Re-Extending Poly(A) Tails
A particularly notable discovery is a new regulatory element called "Pt1 (search)," which is entirely different from the existing TENT4 (search)-based mechanisms. Pt1 was found in the terminal regulatory region of the eel picornavirus genome, and it functions by directly recruiting PAP (Poly(A) Polymerase) (search), the enzyme that synthesizes poly(A) tails.
The mode of action differs from conventional regulatory elements. When the poly(A) tail shortens during the process of mRNA degradation, Pt1 (search) uses PAP to lengthen the tail again. In effect, as the "protective shield" of RNA wears down, Pt1 replenishes it, thereby delaying degradation.
The results were confirmed quantitatively. When Pt1 (search) was attached to standard linear mRNA, the number of adenine bases comprising the poly(A) tail increased from 60 to as many as 194. The mRNA half-life also extended from 7.6 hours to 23.1 hours—an approximately threefold increase. According to the research team, this level of stability is comparable to that of circular RNA, which is known for its high stability.
Implications for mRNA Therapeutics
This result is noteworthy because RNA stability is one of the main challenges in the current development of mRNA vaccines and therapeutics. Linear mRNA is more susceptible to degradation within cells because both ends are exposed. However, using Pt1 (search), it may be possible to extend RNA lifespan while maintaining a linear structure. The research team explains that this technology could evolve to improve the duration of efficacy and protein production, while retaining the manufacturing advantages of linear mRNA.
The significance of this achievement lies in its potential to resolve a bottleneck in mRNA therapeutic development. While mRNA vaccines can generate immune cells even with brief in-body residence, therapeutics become more effective the longer they remain in the body.
The mRNA therapeutics market is growing rapidly. According to market research firm Grand View Research, the mRNA therapeutics market is projected to grow at a compound annual rate of 17%, reaching $31.3 billion (approximately 44.4 trillion won) by 2030.
Limitations and Next Steps
This study remains at the basic research stage, having identified a new principle of RNA regulation and a molecular tool. For practical application in vaccines or therapeutics, it is necessary to further verify protein yield, duration, and safety when Pt1 (search) is used.
"This study represents a large-scale elucidation of the sophisticated strategies viruses use to exploit host cell RNA regulatory systems," said Kim. "The regulatory elements we discovered could become powerful molecular tools capable of overcoming the limitations of existing mRNA therapeutic technologies and significantly enhancing drug efficacy duration."