Herpes Simplex Virus Type 1 Capsid Protein VP26 Interacts with Dynein Light Chains RP3 and Tctex1 and Plays a Role in Retrograde Cellular Transport

Abstract

Cytoplasmic dynein is the major molecular motor involved in minus-end-directed cellular transport along microtubules. There is increasing evidence that the retrograde transport of herpes simplex virus type 1 along sensory axons is mediated by cytoplasmic dynein, but the viral and cellular proteins involved are not known. Here we report that the herpes simplex virus outer capsid protein VP26 interacts with dynein light chains RP3 and Tctex1 and is sufficient to mediate retrograde transport of viral capsids in a cellular model. A library of herpes simplex virus capsid and tegument structural genes was constructed and tested for interactions with dynein subunits in a yeast two-hybrid system. A strong interaction was detected between VP26 and the homologous 14-kDa dynein light chains RP3 and Tctex1. In vitro pull-down assays confirmed binding of VP26 to RP3, Tctex1, and intact cytoplasmic dynein complexes. Recombinant herpes simplex virus capsids were constructed either with or without VP26. In pull-down assays VP26؉ capsids bound to RP3; VP26؊ capsids did not. To investigate intracellular transport, the recombinant viral capsids were microinjected into living cells and incubated at 37°C. After 1 h VP26؉ capsids were observed to co-localize with RP3, Tctex1, and microtubules. After 2 or 4 h VP26؉ capsids had moved closer to the cell nucleus, whereas VP26؊ capsids remained in a random distribution. We propose that VP26 mediates binding of incoming herpes simplex virus capsids to cytoplasmic dynein during cellular infection, through interactions with dynein light chains.

Transport and egress of herpes simplex virus in neurons

“…Recent work in our laboratory suggests that the HSV-1 outer capsid protein pUL35 (also designated VP26) is important for retrograde viral transport [62]. The capsid protein pUL35 was shown to interact with Tctex1 and rp3, both in a yeast two-hybrid system and in vitro, and the interaction was confirmed using recombinant HSV-1 capsids and intact dynein complexes.…”

“…Capsids containing pUL35 colocalised with MTs, Tctex1 and rp3, and moved towards the cell nucleus over time. No movement towards the nucleus was observed for capsids not containing pUL35 [62].…”

“…These tegument proteins are therefore the likely complementary candidates to pUL35 for engaging the dynein/ dynactin complex [65,66,70]. In the case of pUL36 and pUL37, our laboratory has failed to detect a direct interaction with the subunits of dynein using the yeast two-hybrid assay [62]. However, further broader investigations are required to establish whether or not pUL36, pUL37 and pUS3 are involved in binding of the dynein/ dynactin complex.…”

Intracellular trafficking of nonviral vectors

“…170 Numerous viruses have taken advantage of this intracellular transport system and utilize dynein-mediated trafficking to catch a ride to nuclear periphery. [171][172][173][174][175][176] While in some cases intact cytoskeletal elements are Intracellular trafficking of nonviral vectors LK Medina-Kauwe et al required for appropriate nonviral vector trafficking in cells, in other cases, the cytoskeleton may either interfere with intracellular translocation or direct nonviral vectors to undesirable sites within the cell. In many of the studies mentioned earlier, the contribution of the cytoskeleton to vector uptake and vesicle trafficking was described.…”

Deletion or green fluorescent protein tagging of the pUL35 capsid component of pseudorabies virus impairs virus replication in cell culture and neuroinvasion in mice

“…Yeast two-hybrid studies indicated interactions of HSV-1 VP26 with several subunits of the dynein complex, which is involved in intracytoplasmic transport of herpesvirus capsids along microtubules (Douglas et al, 2004;Sodeik et al, 1997). Active capsid transport to the nucleus is considered to be essential for host cell infection, and for transneuronal spread of alphaherpesviruses.…”