Characterization of two homologues of ChaB in Spodoptera litura multicapsid nucleopolyhedrovirus.
ChaB, a putative regulator of ChaA in Escherichia coli (E. coli), and its homologues constitute a multigene family known to occur among bacteria, archaeabacteria and baculoviruses. Distinguished from E. coli ChaB, baculoviruses ChaB proteins lack a charged loop that can bind to Ca2+ and Mg2+. The baculovirus Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) contains two homologues of ChaB, open reading frames (ORFs) 52 (Sl52) and 53 (Sl53). Reverse transcription-PCR and 5' Race analyses indicated that transcription of both SpltMNPV chaB genes occurs by 12 h postinfection and is initiated at a late consensus (A/T)TAAG motif. Immunoblot analysis showed that Sl52 was expressed as a doublet of 23 and 26 kDa in infected S. litura cells, while Sl53 was expressed as a 16 kDa protein. Biochemical fractionation analysis indicated that the 23 kDa form of Sl52 was distributed in both cytoplasm and nucleus of infected cells, whereas the 26 kDa form of Sl52 and Sl53 proteins were only present in nucleus. Further analysis revealed that these proteins are associated with the nucleocapsid of occlusion-derived virus. Using a histone extraction protocol, the Sl53 and 26 kDa form of Sl52 proteins were both detected in the histone H1 fraction. Additionally, column chromatography analysis showed that the Sl52 and Sl53 proteins could interact with nucleic acids. It was proposed that SpltMNPV ChaB might function as DNA binding proteins.
State Key Laboratory of Biocontrol and Institute of Entomology, Zhongshan University, Guangzhou 510275, PR China.
Zhaofei
Z
Li
Lingling
L
Li
Hang
H
Yu
Sainan
S
Li
Yi
Y
Pang
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009696:Nucleic Acids / Q000378:metabolism; D019251:Nucleocapsid / Q000737:chemistry*; D017924:Nucleopolyhedroviruses / Q000737:chemistry*; D010802:Phylogeny; D011485:Protein Binding; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020539:Sequence Analysis, Protein; D018411:Spodoptera / Q000166:cytology / Q000821:virology*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics; D019065:Virus Assembly
C500388:ChaB protein, E coli; D029968:Escherichia coli Proteins; D009696:Nucleic Acids; D012333:RNA, Messenger; D014764:Viral Proteins