Twinkle, Twinkle Little Cryo-EM Star
Posted on by Dr. Francis Collins
The stars are out and shining this holiday season. But there are some star-shaped structures now under study in the lab that also give us plenty of reason for hope. One of them is a tiny virus called bacteriophage phi-6, which researchers are studying in an effort to combat a similar, but more-complex, group of viruses that can cause life-threatening dehydration in young children.
Thanks to a breakthrough technology called cryo-electron microscopy (cryo-EM), NIH researchers recently captured, at near atomic-level of detail, the 3D structure of this immature bacteriophage phi-6 particle in the process of replication. At the points of its “star,” key proteins (red) are positioned to transport clipped, single-stranded segments of the virus’ own genetic information into its newly made shell, or procapsid (blue). Once inside the procapsid, an enzyme (purple) will copy the segments to make the genetic information double-stranded, while another protein (yellow) will help package them. As the procapsid matures, it undergoes dramatic structural changes.
Because the tiny virus is easy to work with in the lab and has a genetic blueprint made of RNA, bacteriophage phi-6 has proven to be a valuable model for studying rotavirus and other more complex, double-stranded RNA viruses that make people sick.
Working in the lab of Alasdair Steven at NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases, Daniel Nemecek and Bernard Heymann produced this cryo-EM image as part of their effort to find new ways to thwart rotavirus infection, which can cause gastrointestinal upset and severe dehydration in young children. Although a vaccine is now available for the four most common strains of rotavirus, the bug still claims the lives of more than 450,000 children ages 5 and under worldwide each year, and is responsible for over 400,000 hospital visits annually in the United States alone . Clearly, more must be done to prevent and treat this childhood health threat—and NIH researchers are on the case.
So, this busy holiday season, I hope you’ll join me in taking a moment to look up at the stars and reflect not only on these scientists, but the many brilliant minds around the world who are working so hard to give us the gift of better health. Happy holidays to one and all, and may this season bring you peace and joy!
 Rotavirus (Centers for Disease Control and Prevention)
Developing the First Rotavirus Vaccine (Intramural Research Program/NIH)
Alasdair Steven (National Institute of Arthritis and Musculoskeletal and Skin Diseases/NIH)
NIH Support: National Institute of Arthritis and Musculoskeletal and Skin Diseases