Scientists at the Gladstone Institutes are studying the functions of a deadly and a potentially lethal virus, cytomegalovirus (CMV), in order to fight against it and provide treatments, reports Medical Xpress.
CMV is one of the world's eight most deadly viruses which fall in the family of viruses such as Epstein-Barr virus (which causes mononucleosis) and varicella-zoster virus (which causes chickenpox). CMV's function which makes it lethal is it replicates quickly and attacks the host cells just long enough produce higher amounts of viruses in the body.
"CMV infects between 50% and 80% of adults worldwide and can often be transmitted from mother to child during pregnancy," said Investigator Leor Weinberger, PhD, who is also an associate professor of biochemistry and biophysics at the University of California, San Francisco (UCSF), with which Gladstone is affiliated, reports Medical Xpress. "While CMV usually lies dormant, it can be dangerous or even deadly for the developing fetus or for those with compromised immune systems -- such as organ-transplant recipients. As a result, we have long sought to understand exactly how CMV infects cells, in the hopes of developing treatments or a vaccine to diminish its presence around the world."
Dr. Weinberger further explained the reason why CMV succeeds. The virus contains 'accelerator circuit' within the CMV's DNA which allows it to reach the optimum levels very quickly much before the host cells can respond.
CMV's genetic code known as Major Immediate-Early Promoter (MIEP) starts the replication process by generating IE2. Researchers showed that excess amount of IE2 can be extremely toxic. CMV also manages the IE2 generation and stops it before it's reached the optimum level, says report in Medical Xpress.
"CMV needs IE2 in order to replicate inside the host cell, but if too much IE2 is produced too quickly, the host cell will be killed before CMV has a chance to spread," said Melissa Teng, a graduate student at the University of California, San Diego (UCSD), a visiting UCSF graduate student and one of the paper's lead authors "But CMV gets around this problem with the so-called 'accelerator circuit,' which helps maintain optimal IE2 levels. This circuit allows CMV to replicate quickly and efficiently, infecting a range of cell types throughout the body."
An experiment was conducted in order to prove the theory right. Scientists infected human cells with two different types of CMV virus, one with ability to generate IE2 accelerator circuit and another which could not. When both these viruses were placed in the same dish, the one which could not generate IE2 accelerator circuit disappeared and the other one spread quickly, says a report in Medical Xpress.
"This impressive work demonstrates a new mechanism for how a relatively simple genetic network can respond to external cues and create the most optimal environment for viral replication," said Gurol Suel, PhD, an associate professor of molecular biology at UCSD who was not involved in the study. "It's quite likely that mechanisms like this one exist in other biological systems, including other viruses."
These findings are also published online in the latest journal Cell.
