title: The Telomerase/vault-associated protein TEP1 is required for vault RNA stability and its association with the vault particle.
abstract: Vaults and telomerase are ribonucleoprotein (RNP) particles that share a common protein subunit, TEP1. Although its role in either complex has not yet been defined, TEP1 has been shown to interact with the mouse telomerase RNA and with several of the human vault RNAs in a yeast three-hybrid assay. An mTep1(-/-) mouse was previously generated which resulted in no apparent change in telomere length or telomerase activity in six generations of mTep1-deficient mice. Here we show that the levels of the telomerase RNA and its association with the telomerase RNP are also unaffected in mTep1(-/-) mice. Although vaults purified from the livers of mTep1(-/-) mice appear structurally intact by both negative stain and cryoelectron microscopy, three-dimensional reconstruction of the mTep1(-/-) vault revealed less density in the cap than previously observed for the intact rat vault. Furthermore, the absence of TEP1 completely disrupted the stable association of the vault RNA with the purified vault particle and also resulted in a decrease in the levels and stability of the vault RNA. Therefore, we have uncovered a novel role for TEP1 in vivo as an integral vault protein important for the stabilization and recruitment of the vault RNA to the vault particle.
authors.affiliation: Department of Biological Chemistry, University of California at Los Angeles, School of Medicine, Los Angeles, California 90095, USA. vkick@mednet.ucla.edu
authors.forename: V A
authors.initials: VA
authors.lastname: Kickhoefer
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: L B
authors.initials: LB
authors.lastname: Kong
authors.forename: B E
authors.initials: BE
authors.lastname: Snow
authors.forename: P L
authors.initials: PL
authors.lastname: Stewart
authors.forename: L
authors.initials: L
authors.lastname: Harrington
authors.forename: L H
authors.initials: LH
authors.lastname: Rome
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D020285:Cryoelectron Microscopy / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D028044:Phosphate-Binding Proteins; D011499:Protein Processing, Post-Translational; D020871:RNA Stability; D016601:RNA-Binding Proteins; D051381:Rats; D019098:Telomerase / Q000378:metabolism*; D020394:Vault Ribonucleoprotein Particles / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D028044:Phosphate-Binding Proteins; D016601:RNA-Binding Proteins; C498415:Tep1 protein, mouse; C498416:Tep1 protein, rat; D020394:Vault Ribonucleoprotein Particles; D019098:Telomerase