NDRG1 facilitates the replication and persistence of Kaposi’s sarcoma-associated herpesvirus by interacting with the DNA polymerase clamp PCNA

Abstract

Kaposi’s sarcoma-associated herpesvirus (KSHV) latently infects host cells and establishes lifelong persistence as an extra-chromosomal episome in the nucleus. To persist in proliferating cells, the viral genome typically replicates once per cell cycle and is distributed into daughter cells. This process involves host machinery utilized by KSHV, however the underlying mechanisms are not fully elucidated. In present study, we found that N-Myc downstream regulated gene 1 (NDRG1), a cellular gene known to be non-detectable in primary B cells and endothelial cells which are the major cell types for KSHV infection in vivo, was highly upregulated by KSHV in these cells. We further demonstrated that the high expression of NDRG1 was regulated by latency-associated nuclear antigen (LANA), the major viral latent protein which tethers the viral genome to host chromosome and plays an essential role in viral genome maintenance. Surprisingly, knockdown of NDRG1 in KSHV latently infected cells resulted in a significant decrease of viral genome copy number in these cells. Interestingly, NDRG1 can directly interact with proliferating cell nuclear antigen (PCNA), a cellular protein which functions as a DNA polymerase clamp during DNA replication. Intriguingly, we found that NDRG1 forms a complex with LANA and PCNA and serves as a scaffold protein bridging these two proteins. We further demonstrated that NDRG1 is critical for mediating LANA to recruit PCNA onto terminal repeat (TR) of KSHV genome, and facilitates viral DNA replication and episome persistence. Taken together, our findings suggest that NDRG1 plays an important role in KSHV viral genome replication, and provide new clues for understanding of KSHV persistence.

NDRG1 facilitates lytic replication of Kaposi’s sarcoma-associated herpesvirus by maintaining the stability of the KSHV helicase

“…In the present study, we further explored the functions of NDRG1 in KSHV lytic replication. Based on previous data, KSHV ORF44 was identified as a novel NDRG1-binding protein [31]. We further demonstrated that the N-terminal domain of NDRG1 binds to the N-terminal region of ORF44.…”

Cystic proliferation of germline stem cells is necessary to reproductive success and normal mating behavior in medaka

“…Ndrg1 homologs have been found in different species of invertebrates and vertebrates (Fang et al, 2014;Kovacevic et al, 2013;Sun et al, 2013). In mammals, it has been well established that Ndrg1 exerts an inhibitory effect on cancer cell proliferation (Chang et al, 2014;McCaig et al, 2011;Xi et al, 2017;Zhang et al, 2019). Additionally, several studies have shown that Ndrg1 is expressed in the gonads of humans, mice, sheep and medaka (Burl et al, 2018;Kikuchi et al, 2019;Lachat et al, 2002;Qu et al, 2019;Stévant and Nef, 2019), however its role in gonadal function and reproduction is still unknown.…”

“…Interestingly, Ndrg1 is involved in the regulation of cell proliferation in different cancers (Chang et al, 2014;McCaig et al, 2011;Xi et al, 2017;Zhang et al, 2019). Moreover, this gene has homologs from mammals (Ndrg1) to fish (ndrg1), C. elegans (ZK1073.1) to fruit fly (Dmel\MESK2), suggesting that NDRG1 is highly conserved among species (Kovacevic et al, 2013;Sun et al, 2013).…”

Cystic proliferation of embryonic germ stem cells is necessary to reproductive success and normal mating behavior in medaka

“…Ndrg1 homologs have been found in different species of invertebrates and vertebrates (Fang et al, 2014;Kovacevic et al, 2013;Sun et al, 2013). In mammals, it has been well established that Ndrg1 exerts an inhibitory effect on cancer cell proliferation (Chang et al, 2014;McCaig et al, 2011;Xi et al, 2017;Zhang et al, 2019). Additionally, several studies have shown that Ndrg1 is expressed in the gonads of humans, mice, sheep and medaka (Burl et al, 2018;Kikuchi et al, 2019;Lachat et al, 2002;Qu et al, 2019;Stévant and Nef, 2019), however its role in gonadal function and reproduction is still unknown.…”

“…In the search for genes that regulate EGSCs proliferation, ndrg1 (n-myc downstream regulated gene 1) is one of the genes that was found to be upregulated in germ cell foxl3 mutants, a switch gene involved in the germline sexual fate decision in medaka (Kikuchi et al, 2019). Interestingly, Ndrg1 has been involved in the regulation of cell proliferation in different cancers (Chang et al, 2014;McCaig et al, 2011;Xi et al, 2017;Zhang et al, 2019).…”