By electrophoretic mobility shift assays , we confirmed DNA binding by VP15 as previously reported and showed that PmFKBP46 also binds with DNA, as was ASP1517 HIF inhibitor suggested by the putative Fulvestrant helix-loophelix structure predicted from its deduced amino acid sequence. With respect to the significance of binding between PmFKBP46 and VP15 in terms of WSSV virion production in host cells, there is still too little information for firm conclusions. The higher intensity of fluorescence by immunocytochemistry for PmFKBP46 in WSSVinfected nuclei than in normal nuclei, might suggest that WSSV recruits PmFKBP46 protein for its genome packaging process or that VP15 is transported to the nucleus by the nuclear targeting capability of PmFKBP46. In a previous report, VP15 was proposed to contain a nuclear targeting sequence necessary for nuclear translocation , but the results as reported would have been the same if VP15 transport depended on its specific binding to a host protein that targeted the nucleus, as speculated here. Further work is needed to determine the actual situation, but it is notable that the nuclear targeting motif in PmFKBP46more clearly resembles themodel motif than that of VP15. It would also be interesting to investigate whether otherWSSV proteins also bind to PmFKBP46. In any case, there is no evidence from published reports that PmFKBP46 is among the 40 proteins reported to be present in the WSSV virion , so even though it binds specifically to VP15 and may be involved in VP15 transport to the nucleus, it must be separated from VP15 during virion assembly. This might occur during the formation of the fibrillar complex of DNA and viral proteins that has been reported to occur prior to DNA packaging in the WSSV nucleocapsid . Such hypotheses could be tested using immunocytochemical analysis of VP15 distribution after PmFKBP46 knockdown or immunogold assays by electron microscopy to examine the ultrastructural locations of PmFKBP46 and VP15 during virion assembly. Also requiring an explanation is the molecular weight discrepancy between the deduced mass of PmFKBP46 and the expressed proteins from shrimp hemocytes and from the bacterial system.