Cell News 3/2013
30
MEETING REPORT
proteins and non-coding RNAs dynamically organize the chro-
matin. While highly compacted and organized, genomic DNA
needs to be accessed by numerous factors to reach versatile
chromatin modification, activity, and modulation.
Contributions by young scientists
A major aim of this workshop is to encourage the participation of
young together with mature scientists from the field of virology
and give them the chance to present their work in 20-minute-
oral presentations. The workshop was attended by numerous
participants from outside of Germany underlining the quality of
the research presented at and the dynamic nature of this work-
shop. In general, the talks covered major viral families including
α
- (HSV-1),
β
- (mCMV, HCMV) and
γ
-herpesviruses (MHV-68,
EBV, KSHV), several other DNA viruses (adenovirus, papilloma vi-
rus, Hepatitis B virus) as well as HIV, Hepatitis C virus and some
more exotic candidates. The presented topics covered various
aspects of virus replication, virus-host interaction and formation
of progeny virions.
Entry of virus particles into host cells is an important topic in
virus research with great potential to apply the insights for an-
tiviral interventions. Enveloped viruses initiate infection by a
virus-based fusion machinery that triggers the merging of host
and virus membranes to eventually release the capsid to the cy-
tosol. Alteration of the cortical actin may often be required for
early steps of virus entry likely induced by a virus-triggered sig-
nalling event. Transport of capsids through the cytoplasm either
of incoming or newly formed particles is another major interest
of virus research. Here, tegument proteins and the relevance of
embedded motifs for interaction with host microtubular motor
proteins are analysed. Similarly, kinetics of capsid transport were
determined and compared between various virus species sugges-
ting that particle transport is primarily governed by host rather
than by virus factors.
Several contributions centered around nuclear structures and
chromatin dynamics perfectly fitting the focus of last years work-
shop. PML nuclear bodies (PML-NB) are intranuclear sites with
functions in DNA repair, transcriptional regulation, chromatin
remodelling, protein degradation, and stress response. Numerous
viral proteins target and destroy PML proteins and structures, in
addition, genomes of various DNA viruses associate with these
functionally important cellular structures. Quite obviously, PML-
NB connect genome replication and gene expression thereby ex-
hibiting pro- and antiviral activities. In addition to PML-NB, the
nuclear envelope was identified to be active in stress response
by a novel type of autophagy called nuclear-envelope derived
autophagy (NEDA).
Quite obviously transcriptional regulation is of utmost impor-
tance for viral propagation. To modulate or interfere with host
expression programs, viral proteins apply various strategies. The
transcriptionally active RNA polymerase II may be differenti-
ally degraded to inhibit antiviral host protein production. Vi-
ral transcription factors are key regulators of viral and cellular
transcription and may regulate chromatin activity by directly
interacting with core histones. Moreover, to exploit the host ma-
chinery for their own benefit, viral factors preferentially export
viral rather than host transcripts out of the nucleus. MiRNAs
either of viral or host origin continue to be of major interest as
factors that regulate and fine-tune viral lytic infections and play
a role during virus-induced transformation of host cells. Virion
formation, transport and release to the surface are research
interests actively persued with the ultimate goal to identify
components that can be attacked by siRNAs and other small mo-
lecules to prevent virion release and thus spread of the infection.
Last but not least, the analysis of viral co-infections indicates a
new trend with clinical relevance.
