Only Sabin type 3 polio vaccine strain mutation reduces viral growth.

2004 MAY 5 - (NewsRx.com & NewsRx.net) -- Only the Sabin type 3 strain mutation significantly reduces viral growth in HeLa and neuroblastoma cells.

"Initiation of poliovirus (PV) protein synthesis is governed by an internal ribosome entry segment structured into several domains including domain V, which is accepted to be important in PV neurovirulence because it harbors an attenuating mutation in each of the vaccine strains developed by A. Sabin. To better understand how these single point mutations exert their effects, we placed each of them into the same genomic context, that of PV type 1," scientists writing in the Journal of Biological Chemistry report.

"Only the mutation equivalent to the Sabin type 3 strain mutation resulted in significantly reduced viral growth both in HeLa and neuroblastoma cells," said Cecile E. Malnou at the Institut Pasteur in Paris and collaborators in France and England. "This correlated with poor translation efficiency in vitro and could be explained by a structural perturbation of the domain V of the internal ribosome entry segment, as evidenced by RNA melting experiments. We demonstrated that reduced cell death observed during infection by this mutant is due to the absence of inhibition of host cell translation.

"We confirmed that this shut-off is correlated principally ...