Experiments conducted by the University of Texas Medical Branch (UTMB) scientists show that a SARS coronavirus protein called nsp1 causes the breakdown of biochemical messages that normally prompt the production of a protein critical to defending the body against viruses.
“The SARS nsp1 protein degrades the messenger RNA instructions sent from DNA to make interferon beta, which is crucial to host immunity,” said UTMB professor of microbiology and immunology Shinji Makino. “This is a very rare phenomenon, and it raises a lot of questions – among them, whether we can make a mutant form of SARS coronavirus that lacks the ability to degrade messenger RNA, which could ultimately lead to the creation of a live attenuated vaccine for SARS.”
Although many viruses interfere with host cells making messenger RNA or translating it into infection-fighting proteins, only one other virus is known to break down messenger RNA: herpes simplex virus (HSV).
Exactly how an RNA virus can preserve its integrity when it makes a protein that breaks down RNA, and whether a mutated non-RNA-degrading SARS coronavirus could constitute a workable SARS vaccine are all issues that Professor Makino’s group intends to pursue.