Purification and characterization of the U-particle, a cellular constituent whose synthesis is stimulated by Mengovirus infection.

ABSTRACT

We have isolated a cellular protein particle whose synthesis is induced by infection with Mengovirus or TMEV. The U-particle inhibits translation in vitro and binds to both capped and uncapped mRNA's. It is spherical, 12 nm in diameter, and is composed of multiple copies of two polypeptide subunits having molecular weights of 23,000 and 25,000 which do not appear to be glycosylated or phosphorylated. U-particles are capable of inhibiting mRNA translation in vitro.