Genes from different chromosomes can team up to make brand-new proteins

For decades, biology's central dogma held that one gene makes one protein. Harvard Medical School researchers have just blown that wide open. A study published in Nature reveals that genes from entirely different chromosomes — even distant ones — can physically loop together and combine their instructions to produce chimeric mRNAs, which then create hybrid proteins that were completely unknown to science until now.

Using a cutting-edge technique called direct RNA sequencing, the team compiled a "dark genome" library of over 30,000 chimeric mRNAs observed in mammalian cells. They then zeroed in on one — a fusion of the GSDMD and TMEM106A genes — and showed it plays a critical role in the immune response in mice, helping regulate pyroptosis, the explosive cell-death process that drives inflammation.

Key Takeaways

• Mice lacking the chimeric protein had ~50% slower immune responses and struggled to clear Salmonella infections
• Mice with elevated chimeric protein levels couldn't survive even mild sepsis-inducing doses
• The Jackson Lab is now investigating chimeric mRNAs linked to cancer, inflammatory disease, and neurodegeneration
• Moderna collaborated with the team to engineer mRNA that modulates chimeric protein production

Why it matters: This discovery essentially adds a new chapter to the human genome playbook. If chimeric proteins are widespread — and researchers suspect they are — they could represent an entirely overlooked class of drug targets, offering fresh hope for diseases that have long stumped medicine.