title: Autographa californica multiple nucleopolyhedrovirus PK-1 is essential for nucleocapsid assembly.
abstract: PK-1 (Ac10) is a baculovirus-encoded serine/threonine kinase and its function is unclear. Our results showed that a pk-1 knockout AcMNPV failed to produce infectious progeny, while the pk-1 repair virus could rescue this defect. qPCR analysis demonstrated that pk-1 deletion did not affect viral DNA replication. Analysis of the repaired recombinants with truncated pk-1 mutants demonstrated that the catalytic domain of protein kinases of PK-1 was essential to viral infectivity. Moreover, those PK-1 mutants that could rescue the infectious BV production defect exhibited kinase activity in vitro. Therefore, it is suggested that the kinase activity of PK-1 is essential in regulating viral propagation. Electron microscopy revealed that pk-1 deletion affected the formation of normal nucleocapsids. Masses of electron-lucent tubular structures were present in cell transfected with pk-1 knockout bacmid. Therefore, PK-1 appears to phosphorylate some viral or cellular proteins that are essential for DNA packaging to regulate nucleocapsid assembly.
authors.affiliation: College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, People's Republic of China. cyliang@yzu.edu.cn
authors.forename: Changyong
authors.initials: C
authors.lastname: Liang
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Xuejuan
authors.initials: X
authors.lastname: Dai
authors.forename: Shuling
authors.initials: S
authors.lastname: Zhao
authors.forename: Yanling
authors.initials: Y
authors.lastname: Hou
authors.forename: Yongli
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dandan
authors.initials: D
authors.lastname: Lan
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Xinwen
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004261:DNA Replication; D015967:Gene Expression Regulation, Viral; D019251:Nucleocapsid / Q000378:metabolism*; D017924:Nucleopolyhedroviruses / Q000201:enzymology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D018411:Spodoptera / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D019065:Virus Assembly; D014779:Virus Replication
chemical_list: D014764:Viral Proteins; D017346:Protein Serine-Threonine Kinases
keywords: AcMNPV; Baculovirus; Nucleocapsid assembly; Protein kinase