Attenuation of rabies virus replication and virulence by picornavirus internal ribosome entry site elements.
Gene expression of nonsegmented negative-strand RNA viruses is regulated at the transcriptional level and relies on the canonical 5'-end-dependent translation of capped viral mRNAs. Here, we have used internal ribosome entry sites (IRES) from picornaviruses to control the expression level of the phosphoprotein P of the neurotropic rabies virus (RV; Rhabdoviridae), which is critically required for both viral replication and escape from the host interferon response. In a dual luciferase reporter RV, the IRES elements of poliovirus (PV) and human rhinovirus type 2 (HRV2) were active in a variety of cell lines from different host species. While a generally lower activity of the HRV2 IRES was apparent compared to the PV IRES, specific deficits of the HRV2 IRES in neuronal cell lines were not observed. Recombinant RVs expressing P exclusively from a bicistronic nucleoprotein (N)-IRES-P mRNA showed IRES-specific reduction of replication in cell culture and in neurons of organotypic brain slice cultures, an increased activation of the beta interferon (IFN-beta) promoter, and increased sensitivity to IFN. Intracerebral infection revealed a complete loss of virulence of both PV- and HRV2 IRES-controlled RV for wild-type mice and for transgenic mice lacking a functional IFN-alpha receptor (IFNAR(-/-)). The virulence of HRV2 IRES-controlled RV was most severely attenuated and could be demonstrated only in newborn IFNAR(-/-) mice. Translational control of individual genes is a promising strategy to attenuate replication and virulence of live nonsegmented negative-strand RNA viruses and vectors and to study the function of IRES elements in detail.
Marschalek
Adriane
A
Max von Pettenkofer-Institute and Gene Center, Ludwig-Maximilians-University, Munich, Germany.
Finke
Stefan
S
Schwemmle
Martin
M
Mayer
Daniel
D
Heimrich
Bernd
B
Stitz
Lothar
L
Conzelmann
Karl-Klaus
KK
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000821:virology; D002460:Cell Line; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018832:Molecular Chaperones; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics; D010849:Picornaviridae / Q000235:genetics; D014176:Protein Biosynthesis; D011818:Rabies / Q000473:pathology; D011820:Rabies virus / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D012270:Ribosomes / Q000378:metabolism*; D015678:Viral Structural Proteins / Q000096:biosynthesis* / Q000235:genetics; D014774:Virulence; D014779:Virus Replication
D018832:Molecular Chaperones; C103961:P phosphoprotein, Rabies virus; D010750:Phosphoproteins; D015678:Viral Structural Proteins