Moon-Jung Song

Human herpesvirus 8 (HHV-8) (also known as Kaposi's sarcoma-associated herpesvirus) encodes a novel noncoding polyadenylated nuclear (PAN) RNA (also known as T1.1 or nut-1) during the early phase of lytic replication. PAN RNA is the most abundant transcript of HHV-8, comprising 80% of total poly(A)-selected transcripts in HHV-8-infected cells during lytic replication. We directly measured the abundance of PAN RNA by visualizing 1.1- to 1.2- kb PAN RNA in an ethidium bromide-stained gel from poly

Gamma-herpesviruses, Epstein-Barr virus, and Kaposi's sarcoma-associated herpesvirus are important human pathogens, because they are involved in tumor development. Murine gamma-herpesvirus-68 (MHV-68 or gammaHV-68) has emerged as a small animal model system for the study of gamma-herpesvirus pathogenesis and host-virus interactions. To identify the genes required for viral replication in vitro and in vivo, we generated 1,152 mutants using signature-tagged transposon mutagenesis on an infectious

RTA (replication and transcription activator; also referred to as ORF50, Lyta, and ART), an immediate-early gene product of Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8, disrupts latency and drives lytic replication. RTA activates the expression of polyadenylated nuclear (PAN) RNA (also known as T1.1 or nut-1) of KSHV. This novel noncoding PAN RNA is the most abundant lytic transcript of KSHV; therefore, studying PAN RNA expression serves as a model system for understanding

Replication and transcription activator (RTA) (also referred to as ORF50), an immediate-early gene product of Kaposi's sarcoma-associated herpesvirus (KSHV)/(human herpesvirus 8), plays a critical role in balancing the viral life cycle between latency and lytic replication. RTA has been shown to act as a strong transcription activator for several downstream genes of KSHV. Direct binding of RTA to DNA is thought to be one of the important mechanisms for transactivation of target genes, while indi

The inflammasome is a molecular platform that stimulates the activation of caspase-1 and the processing of pro-interleukin (IL)-1β and pro-IL-18 for secretion. The NOD-like receptor family, pyrin domain containing 3 (NLRP3) protein is activated by diverse molecules and pathogens, leading to the formation of the NLRP3 inflammasome. Recent studies showed that the NLRP3 inflammasome mediates innate immunity against influenza A virus (IAV) infection. In this study, we investigated the function of th

DExD/H-box helicase 9 (DHX9), or RNA helicase A (RHA), is an abundant multifunctional nuclear protein. Although it was previously reported to act as a cytosolic DNA sensor in plasmacytoid dendritic cells (pDCs), the role and molecular mechanisms of action of DHX9 in cells that are not pDCs during DNA virus infection are not clear. Here, a macrophage-specific knockout and a fibroblast-specific knockdown of DHX9 impaired antiviral innate immunity against DNA viruses, leading to increased virus rep

Replication and transcription activator (RTA), an immediate-early gene product of gamma-2 herpesviruses including Kaposi's sarcoma-associated herpesvirus (KSHV) and murine gamma herpesvirus 68 (MHV-68), plays a critical role in controlling the viral life cycle. RTA acts as a strong transcription activator for several downstream genes of KSHV and MHV-68 through direct DNA binding, as well as via indirect mechanisms. HMGB1 (also called HMG-1) protein is a highly conserved nonhistone chromatin prot

Human norovirus is the leading cause of sporadic gastroenteritis, which is responsible for more than 90% of all nonbacterial gastroenteritis outbreaks. While norovirus infections typically cause mild and self-limiting symptoms lasting 24-48 h, chronic persistent infections can cause severe symptoms. Although recent advances have been made in understanding the molecular characteristics of norovirus infection, no norovirus-specific antiviral drugs, or vaccines are available. Conventional intervent

Our functional mapping study of murine gammaherpesvirus 68 (MHV-68, or gammaHV-68) revealed that a mutant harboring a transposon at the ORF49 locus (ORF49(null)) evidenced a highly attenuated in vitro growth. ORF49 resides adjacent to and in an opposite direction from RTA, the primary switch of the gammaherpesvirus life cycle. A FLAG-tagged ORF49 protein was able to transcomplement ORF49(null), and a revertant of ORF49(null) restored its attenuated growth to a level comparable to that of the wil

Influenza A virus (IAV) infection is a global public health concern. It causes respiratory diseases ranging from mild illness to fatal disease. Natural killer (NK) cells are an innate immune component that kill infected cells and secrete cytokines to modulate the adaptive immune system; they constitute the first-line defense and play important roles in controlling IAV infection. This study evaluated the effect of daily administration of heat-treated Lactobacillus plantarum nF1-fortified yogurt o

Kaposi's sarcoma-associated herpesvirus (KSHV), which belongs to the gammaherpesvirus subfamily, is associated with the pathogenesis of various tumors. Nuclear enzyme poly(ADP-ribose) polymerase 1 (PARP1) catalyzes the polymerization of ADP-ribose units on target proteins. In KSHV-infected cells, PARP1 inhibits replication and transcription activator (RTA), a molecular switch that initiates lytic replication, through direct interaction. Thus, for efficient replication, KSHV has to overcome the m