Mapping Open Reading Frames with Massively Parallel Ribosome Profiling

Understanding how viruses interact with the human immune system and developing effective vaccines requires detailed knowledge of viral proteins. However, identifying the open reading frames (ORFs)—segments of genetic material that can encode proteins—within viral genomes is challenging. Traditional computational methods often struggle to detect these ORFs, and many viruses are too hazardous to culture in laboratory settings. 

To address these obstacles, Shira Weingarten-Gabbay and colleagues from the Broad Institute of MIT and Harvard employed a technique called Massively Parallel Ribosome Profiling (MPRP). This approach, described in a recent Science paper, enabled them to identify over 4,000 ORFs across 679 viral genomes associated with humans. Rather than cultivating dangerous viruses, the researchers created fragments of viral genomes and inserted them into plasmids, which were then transfected into cells. By combining this system with deep sequencing of viral mRNA bound to ribosomes, the team could pinpoint previously unannotated ORFs in a wide range of viruses.

The use of MPRP revealed new viral peptides that play roles in antigen presentation and T cell response, as well as in the regulation of viral protein translation. These discoveries are significant for understanding how viral proteins influence immune responses and the progression of infection. The method also detects peptides that control virus protein expression, which can alter the course of infection and mediate strong host immune reactions.

This strategy allows researchers to survey noncanonical translation across many diverse viruses at once, providing a safer and more comprehensive tool for annotating viral genomes. By circumventing the need to culture live viruses, the technique offers a valuable resource for studying viral proteomics and holds promise for future vaccine development.