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Pseudorabies virus (PrV), a member of alpha-herpesviruses, is
one of the most significant viral pathogens for swine. We had
successfully purified virions of PrV by sucrose centrifugation
gradient. With Kpn I restriction enzyme digestion of viral DNA
and Western blot of viral glycoprotein E , it was demonstrated
that mature PrV virions were located in fraction IV of sucrose
gradient. Initially, actin was found in fraction II, III and IV
of gradient. In order to know the location of actin, virions
were treated either with trypsin to digest the polypeptide
moiety outside the viral envelope or with detergent Triton X-100
to remove the envelope of PrV prior to Western blotting. And we
found that viral associated actin was resistant to trypsin
digestion, indicating that actin is located inside the virion.
To understand how actin plays a role in PrV life cycle, we added
cytochalasin D, a drug inhibiting F actin formation, to PrV-
infected MDBK cells, then the plaque formation of PrV was
examined. The results showed that cytochalasin D could reduce
the size and number of PrV plaques in MDBK cells. On the other
hand, we also found that heat shock proteins 70 ( HSP70 ) were
present in all three fractions and the extracellular-regulated
kinase 2 ( ERK- 2 ) could be detected in fraction II and III.
Following Triton treatment, the heat shock protein was not
detectable by Western blotting, suggesting that it was outside
to the viral envelope. Taken together, our results suggested
that certain cellular proteins may play important roles in PrV
life cycle.
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