A Gammaherpesvirus Noncoding RNA Is Essential for Hematogenous Dissemination and Establishment of Peripheral Latency


Feldman E. R. , Kara M. , Oko L. M. , Grau K. R. , Krueger B. J. , Zhang J., ...More

MSPHERE, vol.1, no.2, 2016 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 1 Issue: 2
  • Publication Date: 2016
  • Doi Number: 10.1128/msphere.00105-15
  • Title of Journal : MSPHERE
  • Keywords: TMER, dissemination, herpesviruses, latency, miRNA, noncoding RNA, viral pathogenesis, DEFICIENT MICE, B-CELLS, INFECTION, MICRORNAS, SEQUENCE

Abstract

Recent intense investigations have uncovered important functions for a diverse array of novel noncoding RNA (ncRNA) species, including microRNAs (miRNAs) and long noncoding RNAs. Not surprisingly, viruses from multiple families have evolved to encode their own regulatory RNAs; however, the specific in vivo functions of these ncRNAs are largely unknown. The human gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are highly ubiquitous pathogens that are associated with the development of a wide range of malignancies, including Burkitt's lymphoma, Hodgkin's lymphoma, nasopharyngeal carcinoma, and Kaposi's sarcoma. Like EBV and KSHV, murine gammaherpesvirus 68 (MHV68) establishes lifelong latency in B cells and is associated with lymphoproliferative disease and lymphoma. Similar to the EBV-encoded small RNA (EBER)-1 and -2, MHV68 encodes eight 200- to 250-nucleotide polymerase III-transcribed ncRNAs called TMERs (tRNA-miRNA-encoded RNAs), which are highly expressed in latently infected cells and lymphoproliferative disease. To define the in vivo contribution of TMERs to MHV68 biology, we generated a panel of individual TMER mutant viruses. Through comprehensive in vivo analyses, we identified TMER4 as a key mediator of virus dissemination. The TMER4 mutant virus replicated normally in lungs and spread with normal kinetics and distribution to lung-draining lymph nodes, but it was significantly attenuated for infection of circulating blood cells and for latency establishment at peripheral sites. Notably, TMER4 stem-loops but not miRNAs were essential for wild-type TMER4 activity. Thus, these findings revealed a crucial miRNA-independent function of the TMER4 ncRNA in MHV68 hematogenous dissemination and latency establishment.