Sorin M, Davies K, Cheng G, Kalpana GV; Conference on Retroviruses and Opportunistic Infections (11th : 2004 : San Francisco, Calif.).

Program Abstr Conf Retrovir Oppor Infect 11th 2004 San Franc Calif. 2004 Feb 8-11; 11: abstract no. 362.

Albert Einstein Coll. of Med., Bronx, NY, USA

BACKGROUND: INI1/hSNF5, a component of the chromatin remodeling SWI/SNF complex, and a tumor suppressor, directly interacts with HIV-1 integrase. We previously demonstrated that truncated version of INI1/hSNF5, containing minimal IN-binding domain, trans-dominantly inhibits HIV-1 particle production. Tumor-derived INI-/- cells exhibit reduced level of virus particle production, which is complemented by INI1/hSNF5. Furthermore, INI1/hSNF5 is incorporated into HIV-1 virions.METHODS: We have used a combination of biochemical and genetic methods to analyze mechanism, specificity and stoichiometry of INI1/hSNF5 incorporation into virions. Yeast two-hybrid screen, followed by GST pulldowns were used to identify interacting partners for INI1/hSNF5. siRNA approach was used to abrogate expression of specific cellular factors in producer cells.RESULTS: We have determined that incorporation of INI1/hSNF5 into virions is highly specific to HIV-1. Stoichiometric analysis has revealed that at least one molecule of INI1/hSNF5 per two molecules of IN is packaged in the virus particle. Analysis of INI1/hSNF5-interacting proteins identified SIN3A-associated protein 18 (SAP18) as a binding partner. The SAP18-INI1/hSNF5 interaction is direct. Furthermore, SAP18 is specifically incorporated into HIV-1 particles. SAP18 is a component of HDAC complex. We have discovered that other components of HDAC complex also get specifically incorporated into HIV-1 particles. To determine if ability of HDAC components to get incorporated into virus particles is linked to functional interaction of INI1/hSNF5 with HIV-1 integrase, we have examined mutant virions deleted of IN, and have found that they no longer incorporate INI1/hSNF5 and HDAC components. To explore the functional significance of incorporation of INI1/hSNF5 and HDAC components into HIV-1 particles, we are using RNA interference to abrogate expression of these cellular factors in producer cell lines, and examining ability of such cells to support HIV-1 replication.CONCLUSIONS: INI1/hSNF5 is specifically incorporated into HIV-1 virions in an IN-dependent manner. INI1/hSNF5 directly interacts with SAP18 component of HDAC complex. It appears that IN recruits SAP18 and other components of HDAC complex into virions via its interaction with INI1/hSNF5.

Publication Types:

• Meeting Abstracts

Keywords:

• Cell Line
• Chromatin
• DNA-Binding Proteins
• Genes, Tumor Suppressor
• HIV Integrase
• HIV-1
• Repressor Proteins
• SIN3A transcription factor
• SNF5 protein, S cerevisiae
• Saccharomyces cerevisiae
• Virion
• genetics
• metabolism

Other ID:

• GWAIDS0031685

UI: 102271322

From Meeting Abstracts