Vesicular Nucleo-Cytoplasmic Transport-Herpesviruses as Pioneers in Cell Biology.

Thomas Mettenleiter

doi:10.3390/v8100266

Abstract

Herpesviruses use a vesicle-mediated transfer of intranuclearly assembled nucleocapsids through the nuclear envelope (NE) for final maturation in the cytoplasm. The molecular basis for this novel vesicular nucleo-cytoplasmic transport is beginning to be elucidated in detail. The heterodimeric viral nuclear egress complex (NEC), conserved within the classical herpesviruses, mediates vesicle formation from the inner nuclear membrane (INM) by polymerization into a hexagonal lattice followed by fusion of the vesicle membrane with the outer nuclear membrane (ONM). Mechanisms of capsid inclusion as well as vesicle-membrane fusion, however, are largely unclear. Interestingly, a similar transport mechanism through the NE has been demonstrated in nuclear export of large ribonucleoprotein complexes during Drosophila neuromuscular junction formation, indicating a widespread presence of a novel concept of cellular nucleo-cytoplasmic transport.

Highlights

Herpesviruses use a vesicle-mediated transfer of intranuclearly assembled nucleocapsids through the nuclear envelope (NE) for final maturation in the cytoplasm
It has become clear in the last decade that they leave the nucleus and traverse the nuclear envelope (NE) by a vesicle-mediated process that entails budding of nucleocapsids at the inner nuclear membrane (INM), thereby forming a primary enveloped virion in the perinuclear space
The primary envelope fuses with the outer nuclear membrane (ONM)

Summary

Introduction

Herpesviruses use a vesicle-mediated transfer of intranuclearly assembled nucleocapsids through the nuclear envelope (NE) for final maturation in the cytoplasm. Two proteins that are conserved in sequence between members of the family Herpesviridae (i.e., the ‘classical’ herpesviruses) within the order Herpesvirales form a heterodimeric nuclear egress complex (NEC). The C-terminally membrane-bound component (designated pUL34 in the cytomegalovirus (HCMV) [13,14] (Figure 1).

Results

Conclusion