Structure and transcription of the Helicoverpa armigera densovirus (HaDV2) genome and its expression strategy in LD652 cells.
Densoviruses (DVs) are highly pathogenic to their hosts. However, we previously reported a mutualistic DV (HaDV2). Very little was known about the characteristics of this virus, so herein we undertook a series of experiments to explore the molecular biology of HaDV2 further.



Phylogenetic analysis showed that HaDV2 was similar to members of the genus Iteradensovirus. However, compared to current members of the genus Iteradensovirus, the sequence identity of HaDV2 is less than 44% at the nucleotide-level, and lower than 36, 28 and 19% at the amino-acid-level of VP, NS1 and NS2 proteins, respectively. Moreover, NS1 and NS2 proteins from HaDV2 were smaller than those from other iteradensoviruses due to their shorter N-terminal sequences. Two transcripts of about 2.2 kb coding for the NS proteins and the VP proteins were identified by Northern Blot and RACE analysis. Using specific anti-NS1 and anti-NS2 antibodies, Western Blot analysis revealed a 78 kDa and a 48 kDa protein, respectively. Finally, the localization of both NS1 and NS2 proteins within the cell nucleus was determined by using Green Fluorescent Protein (GFP) labelling.



The genome organization, terminal hairpin structure, transcription and expression strategies as well as the mutualistic relationship with its host, suggested that HaDV2 was a novel member of the genus Iteradensovirus within the subfamily Densovirinae.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuan Ming Yuan Road, Beijing, 100193, People's Republic of China.|Tobacco Research Institute, Chinese Academy of Agricultural Sciences, No. 11 Ke Yuan Jing Si Road, Qingdao, 266101, People's Republic of China.
Pengjun
P
Xu
Crop and Environment Sciences, Harper Adams University, Newport, TF10 8NB, UK.
Robert I
RI
Graham
Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
Kenneth
K
Wilson
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuan Ming Yuan Road, Beijing, 100193, People's Republic of China. kmwu@ippcaas.cn.
Kongming
K
Wu
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics; D017990:Densovirus / Q000145:classification* / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D008970:Molecular Weight; D016366:Open Reading Frames; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic; D017361:Viral Nonstructural Proteins / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics
D004279:DNA, Viral; C106202:NS1 protein, parvovirus; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins
Densovirus; Expression; HaDV2; Transcription