Inhibition of Ran guanosine triphosphatase-dependent nuclear transport by the matrix protein of vesicular stomatitis virus.

Transport of macromolecules into and out of nuclei, essential steps in gene expression, are potential points of control. The matrix protein (M protein) of vesicular stomatitis virus (VSV) was shown to block transport of RNAs and proteins between the nucleus and cytoplasm of Xenopus laevis oocytes. The pattern of inhibition indicated that M protein interfered with transport that is dependent on the ras-like nuclear guanosine triphosphatase (GTPase) Ran-TC4 and its associated factors. This inhibition of nuclear transport by M protein explains several observations about the effects of VSV infection on host cell gene expression and suggests that RNA export is closely coupled to protein import.