The essential role of clathrin-mediated endocytosis in yellow head virus propagation in the black tiger shrimp Penaeus monodon

• Clathrin coat AP17 gene was up-regulated 3-fold at 12 h post YHV infection.
• Clathrin coat AP17 was also up-regulated at protein level upon YHV infection.
• Knockdown of clathrin coat AP17 gene reduced YHV replicativity by 32-fold.
• Chlorpromazine treated shrimp exhibited significantly low levels of YHV infection.
• We propose YHV is internalized into host cells via clathrin-mediated endocytosis.

Yellow head virus (YHV) is one of the most widespread viruses seriously affecting black tiger shrimp (Penaeus monodon) cultivation. A previous microarray study demonstrated that clathrin coat assembly protein 17 (AP17) was significantly up-regulated after YHV infection (Pongsomboon et al., 2011). Clathrin coat AP17 is a part of the assembly protein σ2 (AP-2) complex which is involved in clathrin-mediated endocytosis. Quantitative RT-PCR (qRT-PCR) revealed that the clathrin coat AP17 gene was up-regulated 3-fold at 12 h post YHV infection. In addition, immunofluorescence microscopy showed that clathrin coat AP17 was highly expressed in the cytoplasm of the YHV-infected hemocytes. Knockdown of the clathrin coat AP17 gene dramatically reduced YHV replicativity by 32-fold. Interestingly, shrimp pre-treated with chlorpromazine, a commercial drug that inhibits clathrin-dependent endocytosis, exhibited significantly low levels of YHV infection. Taken together, these results suggest that clathrin-mediated endocytosis is involved in YHV propagation in P. monodon.