Functional characterization of Ebola virus L-domains using VSV recombinants.

VSV recombinants containing the overlapping L-domain sequences from Ebola virus VP40 (PTAPPEY) were recovered by reverse-genetics. Replication kinetics of M40-WT, M40-P24L, and M40-Y30A were indistinguishable from VSV-WT in BHK-21 cells, whereas the double mutant (M40-P2728A) was defective in budding. Insertion of the Ebola L-domain region into VSV M protein was sufficient to alter the dependence on host proteins for efficient budding. Indeed, M40 recombinants containing a functional PTAP motif specifically incorporated endogenous tsg101 into budding virions and were dependent on tsg101 expression for efficient budding. Thus, VSV represents an excellent negative-sense RNA virus model for elucidating the functional aspects and diverse host interactions associated with the L-domains of Ebola virus.