title: White spot syndrome virus protein ICP11: A histone-binding DNA mimic that disrupts nucleosome assembly.
abstract: White spot syndrome virus (WSSV) is a large ( approximately 300 kbp), double-stranded DNA eukaryotic virus that has caused serious disease in crustaceans worldwide. ICP11 is the most highly expressed WSSV nonstructural gene/protein, which strongly suggests its importance in WSSV infection; but until now, its function has remained obscure. We show here that ICP11 acts as a DNA mimic. In crystal, ICP11 formed a polymer of dimers with 2 rows of negatively charged spots that approximated the duplex arrangement of the phosphate groups in DNA. Functionally, ICP11 prevented DNA from binding to histone proteins H2A, H2B, H3, and H2A.x, and in hemocytes from WSSV-infected shrimp, ICP11 colocalized with histone H3 and activated-H2A.x. These observations together suggest that ICP11 might interfere with nucleosome assembly and prevent H2A.x from fulfilling its critical function of repairing DNA double strand breaks. Therefore, ICP11 possesses a functionality that is unique among the handful of presently known DNA mimic proteins.
authors.affiliation: Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Hao-Ching
authors.initials: HC
authors.lastname: Wang
authors.forename: Han-Ching
authors.initials: HC
authors.lastname: Wang
authors.forename: Tzu-Ping
authors.initials: TP
authors.lastname: Ko
authors.forename: Yu-May
authors.initials: YM
authors.lastname: Lee
authors.forename: Jiann-Horng
authors.initials: JH
authors.lastname: Leu
authors.forename: Chun-Han
authors.initials: CH
authors.lastname: Ho
authors.forename: Wei-Pang
authors.initials: WP
authors.lastname: Huang
authors.forename: Chu-Fang
authors.initials: CF
authors.lastname: Lo
authors.forename: Andrew H-J
authors.initials: AH
authors.lastname: Wang
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D019281:Dimerization; D006434:Hemocytes / Q000821:virology; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism; D033561:Penaeidae / Q000821:virology; D011485:Protein Binding / Q000502:physiology; D020836:Protein Structure, Quaternary / Q000502:physiology; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism; D046848:White spot syndrome virus 1 / Q000737:chemistry* / Q000378:metabolism
chemical_list: D006657:Histones; D009707:Nucleosomes; D014764:Viral Proteins; D004247:DNA