Gene order rearrangement of the M gene in the rabies virus leads to slower replication.

The matrix protein (M) is one of only five genes in the RV genome and is an important multifunctional protein. Besides to allow for the release of newly replicated virions pairing with G, the M protein also functions in virus replication, pathogenicity, and host cell apoptosis. The goal of present study is to generate recombinant viruses with M gene rearranged, thus laying the foundation for further exploring what will happen when the gene for M is relocated on the RV single-strand RNA. We used rHEP-Flury, an attenuated virus that remains virulent for less than 3 days in sucking mice, to reshuffle the M gene, using an approach that leaves the other viral nucleotide sequence intact. Two viruses with translocated M genes (N1M2 and N1M4) were recovered from each of the rearranged cDNAs, whose gene order is 3'-N-M-P-G-L-5' and 3'-N-P-G-M-L-5' respectively. The growth dynamics of these viruses showed slower replication than the wild-type virus in multiple-step growth curves, but they can grow to a comparable titer in tests of single-step growth curves. Further experimentation with these rearranged viruses will provide insights into the relationships between genome structure and virus phenotypes.