Identification of a novel cellular transcriptional repressor interacting with the latent nuclear antigen of Kaposi's sarcoma-associated herpesvirus

Hong Yi Pan, Yan Jin Zhang, Xin Ping Wang, Jian Hong Deng, Fu Chun Zhou, Shou Jiang Gao

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The latent nuclear antigen (LNA) of Kaposi's sarcoma-associated herpesvirus (KSHV) has an essential role in viral latent infection. LNA maintains the stability of KSHV episomes and modulates the expression of cellular genes. A novel cellular protein KLIP1 was identified to interact with LNA through yeast two-hybrid screening, and confirmed by a glutathione S-transferase pull down assay. Domain mapping showed that KLIP1 interacted with the N-terminal domain of LNA. Northern blot hybridization with a KLIP1 probe identified a major transcript of 1.8 kb and a minor transcript of 2.8 kb. cDNA library screening and 5′-RACE revealed that the major transcript encoded an open-reading-frame of 1,257 bp and had a 5′-untranslated region of 73 nucleotides. The major KLIP1 transcript was ubiquitously present in different cell types examined. A KLIP1 synthetic peptide antibody detected a doublet of 58-kDa and 63-kDa proteins in a Western blot assay. KLIP1 had two putative nuclear localization signals and showed punctate nuclear localization when expressed as a GFP-fusion protein. KLIP1 interacted with LNA in vivo, as demonstrated by coimmunoprecipitation using KSHV-infected cells and colocalization when they were expressed as GFP- and DsRed-fusion proteins, respectively. Consistent with its interaction with LNA, nuclear localization, and possession of two leucine zipper motifs, KLIP1 behaved like a transcriptional factor and repressed herpes simplex virus thymidine kinase (TK) promoter activity in a mammalian one-hybrid assay. In addition, cotransfection with LNA alleviated the transcriptional repression effect of KLIP1 on TK promoter activity. These results suggest that KLIP1 is a new member of cellular transcriptional repressors, and that LNA is involved in deregulating cellular transcription process.

Original languageEnglish (US)
Pages (from-to)9758-9768
Number of pages11
JournalJournal of virology
Volume77
Issue number18
DOIs
StatePublished - Sep 2003

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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