Identification and characterization of Risp
type: CreativeWork
description: The aim of this study was to characterize the role of Rev-interacting cellular proteins in controlling the function of Rev in the host cell. The HIV-1 protein Rev plays an essential role in the temporal regulation of the virus gene expression by stimulating the expression of viral structural proteins. Rev enhances the nucleocytoplasmic transport and the translation of unspliced and single spliced viral mRNAs by binding with high affinity to a specific target element on the HIV-RNA. It was assumed that interaction with cellular factors is essential for Rev function. At the onset of this study, only a few potential cofactors were known with no clearly defined functional relevance. So we decided to search for new Rev-interacting factors using the yeast two-hybrid system. In this work a new Rev-interacting protein has been identified, by screening a Jurkat T cell cDNA library. The protein was termed Risp (Rev-interacting shuttle protein), because it shuttles between the nuclear and the cytoplasmic compartments. The Risp gene is widely expressed in human cells and conserved among various species, most probably as part of a larger gene. High amino acid homology (99%) with the C-terminal part of a large brain cDNA clone for KIAA0592 protein has been found, whereas no obvious homology to proteins with known function was observed. However, a weak and partial similarity appeared with several RNA-/DNA-binding and shuttle proteins. This might indicate that the Risp protein - or the larger protein containing it - could be a member of a new family of nucleocytoplasmic shuttle proteins with RNA-/DNA-binding function. Next, the intracellular localization and shuttling of Risp was investigated. In HeLa cells Risp- GFP localized in both nuclear and cytoplasmic compartments, but clearly accumulated in the cytoplasm, indicating the presence of a strong nuclear export signal (NES). The identification of a NES sequence was confirmed by deletion analysis of Risp and by nuclear microinject…
abstract: The aim of this study was to characterize the role of Rev-interacting cellular proteins in controlling the function of Rev in the host cell. The HIV-1 protein Rev plays an essential role in the temporal regulation of the virus gene expression by stimulating the expression of viral structural proteins. Rev enhances the nucleocytoplasmic transport and the translation of unspliced and single spliced viral mRNAs by binding with high affinity to a specific target element on the HIV-RNA. It was assumed that interaction with cellular factors is essential for Rev function. At the onset of this study, only a few potential cofactors were known with no clearly defined functional relevance. So we decided to search for new Rev-interacting factors using the yeast two-hybrid system. In this work a new Rev-interacting protein has been identified, by screening a Jurkat T cell cDNA library. The protein was termed Risp (Rev-interacting shuttle protein), because it shuttles between the nuclear and the cytoplasmic compartments. The Risp gene is widely expressed in human cells and conserved among various species, most probably as part of a larger gene. High amino acid homology (99%) with the C-terminal part of a large brain cDNA clone for KIAA0592 protein has been found, whereas no obvious homology to proteins with known function was observed. However, a weak and partial similarity appeared with several RNA-/DNA-binding and shuttle proteins. This might indicate that the Risp protein - or the larger protein containing it - could be a member of a new family of nucleocytoplasmic shuttle proteins with RNA-/DNA-binding function. Next, the intracellular localization and shuttling of Risp was investigated. In HeLa cells Risp- GFP localized in both nuclear and cytoplasmic compartments, but clearly accumulated in the cytoplasm, indicating the presence of a strong nuclear export signal (NES). The identification of a NES sequence was confirmed by deletion analysis of Risp and by nuclear microinject…
author: Ceccherini-Silberstein, Francesca
date published: 2001-07-20
date modified: 2026-07-24T02:51:33Z
provider: Ludwig Maxmilians Universität München
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Ludwig-Maximilians-Universität