KSHV encoded LANA recruits Nucleosome Assembly Protein NAP1L1 for regulating viral DNA replication and transcription

Namrata Gupta,Subhash C Verma,Suhani Thakker

doi:10.1038/srep32633

Namrata Gupta, Subhash C Verma + Show 1 more

Open Access

https://doi.org/10.1038/srep32633

Copy DOI

Journal: Scientific Reports	Publication Date: Sep 7, 2016
Citations: 15	License type: CC BY 4.0

Affiliation: University of Nevada Reno

Abstract

The establishment of latency is an essential for lifelong persistence and pathogenesis of Kaposi’s sarcoma-associated herpesvirus (KSHV). Latency-associated nuclear antigen (LANA) is the most abundantly expressed protein during latency and is important for viral genome replication and transcription. Replication-coupled nucleosome assembly is a major step in packaging the newly synthesized DNA into chromatin, but the mechanism of KSHV genome chromatinization post-replication is not understood. Here, we show that nucleosome assembly protein 1-like protein 1 (NAP1L1) associates with LANA. Our binding assays revealed an association of LANA with NAP1L1 in KSHV-infected cells, which binds through its amino terminal domain. Association of these proteins confirmed their localization in specific nuclear compartments of the infected cells. Chromatin immunoprecipitation assays from NAP1L1-depleted cells showed LANA-mediated recruitment of NAP1L1 at the terminal repeat (TR) region of the viral genome. Presence of NAP1L1 stimulated LANA-mediated DNA replication and persistence of a TR-containing plasmid. Depletion of NAP1L1 led to a reduced nucleosome positioning on the viral genome. Furthermore, depletion of NAP1L1 increased the transcription of viral lytic genes and overexpression decreased the promoter activities of LANA-regulated genes. These results confirmed that LANA recruitment of NAP1L1 helps in assembling nucleosome for the chromatinization of newly synthesized viral DNA.

Highlights

The establishment of latency is an essential for lifelong persistence and pathogenesis of Kaposi’s sarcoma-associated herpesvirus (KSHV)
Since Latency-associated nuclear antigen (LANA) is required for terminal repeat (TR)-mediated replication, we hypothesized that recruitment of nucleosome assembly protein 1-like protein 1 (NAP1L1) may be important for the assembly of nucleosomes on the newly replicated DNA
KSHV is closely linked to multiple human malignancies, including Kaposi’s sarcoma (KS), primary effusion lymphomas (PELs) and multicentric Castleman’s disease[1,2]

Summary

Introduction

The establishment of latency is an essential for lifelong persistence and pathogenesis of Kaposi’s sarcoma-associated herpesvirus (KSHV). Latency-associated nuclear antigen (LANA) is the most abundantly expressed protein during latency and is important for viral genome replication and transcription. Depletion of NAP1L1 increased the transcription of viral lytic genes and overexpression decreased the promoter activities of LANAregulated genes These results confirmed that LANA recruitment of NAP1L1 helps in assembling nucleosome for the chromatinization of newly synthesized viral DNA. LANA is a nuclear protein with 1162 amino acids and is 220–230 kDa in size It interacts with various cellular and viral proteins to regulate transcription, cellular signaling, viral DNA replication, and genome maintenance[3]. Recent studies have demonstrated that LANA-recruited KAP1 (Krüppel-associated box domain-associated protein 1), a transcriptional repressor, plays a critical role in the silencing of a lytic gene’s expression to facilitate the establishment of latency[20]

Methods

Results

Conclusion