Structure and transcription of the glycoprotein gene of attenuated HEP-Flury strain of rabies virus

An L (polymerase)-deficient rabies virus defective interfering particle RNA is replicated and transcribed by heterologous helper virus L proteins

A rabies virus-derived defective interfering particle (DI) was isolated and characterized. The DI genome contained an internal deletion of 6.4 kb spanning the 3' moiety of the pseudogene region (psi) and most of the L gene. DI-specific monocistronic N, NS, and M mRNAs as well as a G/L fusion mRNA were transcribed in cells coinfected with DI and helper virus. In addition, polycistronic DI RNAs and standard virus RNAs with internal A stretches and intergenic regions were found. Superinfection experiments showed that heterologous rabies-related viruses (Lyssavirus serotypes 2, 3, and 4) can complement the L deficiency of the DI genome. The heterologous polymerase proteins recognize correctly the replicational and transcriptional signal sequences of the Lyssavirus serotype 1-derived DI.

Fatty acylation of rabies virus proteins

The fatty acylation of rabies virus (CVS strain) proteins was investigated. [3H]palmitic acid was found to be incorporated into the glycoprotein G and to a lesser extent into the membrane-associated protein M2. The fatty acid linkage on G was sensitive to sodium borohydride, mercaptoethanol, and hydroxylamine, indicating that the linkage was of the thiolester type. Bromelain digestion indicated that the palmitoylation site on G was located in the intracytoplasmic domain or in the transmembrane domain in which there is only one cysteine in position 461. Therefore, palmitoylation is likely to occur at this position. In the case of M2, the linkage was also sensitive to hydroxylamine and sodium borohydride and to a lesser extent to mercaptoethanol, suggesting that the linkage also occurred on a cysteine.

PCR technique as an alternative method for diagnosis and molecular epidemiology of rabies virus

We have investigated the PCR amplification technique of viral nucleic acids as an alternative protocol for diagnosis and epidemiological studies of rabies virus. A primer set mapping in the nucleoprotein cistron allowed a specific and sensitive amplification of infected brain material, fulfilling the diagnosis requirements. One hundred samples checked by Southern or dot-blot analysis using both radioactive and non-radioactive probes showed identical results in parallel with routine techniques. For molecular epidemiological studies we selected another set of conserved primers flanking the highly evolutive pseudogene (psi gene) region. This set was found to be efficient for all tested fixed rabies virus strains or wild rabies virus isolates as well as the rabies-related Mokola virus. We describe a progressive characterization of the strain that could be extended from rapid typing by a limited panel of restriction enzymes, to the ultimate identification of the nucleotide sequence by an original direct sequencing technique of amplified segments.

The nucleotide sequences of intergenic regions between nine genes of pneumonia virus of mice establish the physical order of these genes in the viral genome

We have cloned eight intergenic regions from the Pneumovirus pneumonia virus of mice that link the nine small and medium sized genes previously described (Chambers et al., 1990). The nucleotide sequences of the clones confirm the locations of these genes and their mRNA transcripts in the viral genome. The intergenic regions vary in size from 2-56 nucleotides and show only faint homology to each other or to their analogues in respiratory syncytial virus. Sequence alignments suggest that the location of the transcriptional start site for the mRNA encoding the major nucleocapsid protein of pneumonia virus of mice and respiratory syncytial virus may have altered during virus evolution by gain or loss of a transcriptional start signal.