Direct activation of the human major vault protein gene by DNA-damaging agents.

Vaults are barrel-shaped cytoplasmic ribonucleoprotein particles composed of three proteins. One of the components, the major vault protein (MVP) initially named the lung resistance-related protein (LRP), was found to be overexpressed in various multidrug resistant cancer cell lines and clinical samples. In this study, we investigated whether anticancer drugs could directly induce MVP protein or gene expression in the SW-620 human colorectal cancer cell line, in which MVP has been shown to be induced by the differentiation-inducing agent, sodium butyrate (NaB).

Characterization of MVP and VPARP assembly into vault ribonucleoprotein complexes.

Vaults are barrel-shaped cytoplasmic ribonucleoprotein particles composed of three proteins: the major vault protein (MVP), the vault poly(ADP-ribose)polymerase (VPARP), and the telomerase-associated protein 1, together with one or more small untranslated RNAs. To date, little is known about the process of vault assembly or about the stability of vault components. In this study, we analyzed the biosynthesis of MVP and VPARP, and their half-lives within the vault particle in human ACHN renal carcinoma cells.