U team makes virus finding

Mike Zacharias

University researchers, along with colleagues in California, have discovered a molecular motor designed for packaging DNA in viruses.

This motor, found in a bacterial virus not seen in humans, plays a significant role in the life cycle and spreading of a virus. And this discovery could be used as a model for studying and treating human viruses such as herpes and shingles.

“One of the problems we have in this life is that there are very few antiviral agents that are effective,” said Dwight Anderson, a University professor of oral microbiology and one of the virus researchers.

A double-strand DNA virus – which looks like an oval-shaped shell with a tail – enters a cell, where it replicates both its DNA and the proteins that make up the shell. After replication, the molecular motor on the shell pulls in a long strand of DNA, packing it under extremely high pressure into the shell.

The infected cell eventually becomes overly packed with the virus and explodes, propelling the virus toward more cells and aiding its expansion.

The DNA packaging motor might be a new focus in the efforts to battle some double-stranded viruses, Anderson said. These includes herpes, chicken pox and shingles.

Some researchers hope the research done on the motor could help fight the herpes virus, said microbiology professor Jay Brown of the University of Virginia’s medical school.

“I would think it would be a very good target,” Brown said. “If you can block this process … you can stop the growth of herpes viruses.”

The DNA packaging motor is also extremely strong, Anderson said.

“On a weight basis, it’s 10 times stronger than your car motor,” Anderson said. If the shell containing DNA was magnified 600,000 times, the shell would measure only an inch in diameter and the unpackaged strand of DNA more than thirteen feet long.

Currently, double-stranded DNA viruses with similar composition to the virus in Anderson’s study are combatted with a variety of drugs.

But these drugs, Anderson said, are not completely virus-specific.

“You can inhibit viruses that are in cells by adding a number of chemicals, but you also tend to kill the cells,” Anderson said. “So they are not highly selective.”

Anderson and Shelley Grimes of the University’s departments of microbiology and dentistry worked with four researchers from the University of California-Berkeley in studying the motor, the first of its kind discovered. Their breakthrough was the cover story for Nature magazine’s Oct. 18 issue.

Anderson said people do not understand much about viral infections, but understanding less complicated viruses is another step toward learning more about others.

“If you understand a simple virus, someday you are going to understand the complex ones,” Anderson said.


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