Detection of the L protein of tomato spotted wilt virus

The 5'-terminal and 3'-terminal parts of the single open reading frame (ORF) in the L RNA of tomato spotted wilt virus (TSWV) were expressed using a prokaryotic expression system. Using antibodies raised against the translational products obtained a 330-kDa protein could be specifically detected in preparations of purified virions and in nucleocapsid preparations from TSWV-infected leaf tissue. The results obtained indicate that the L protein of TSWV, though much larger than that of the animal-infecting bunyaviruses, is present in virus particles in an unprocessed, intact form.