Characterization of structural proteins of Solenopsis invicta virus 1.
Purification of Solenopsis invicta virus 1 (SINV-1) from its host, S. invicta, and subsequent examination by electron microscopy revealed a homogeneous fraction of spherical particles with a diameter of 30-35 nm. Quantitative PCR with SINV-1-specific oligonucleotide primers verified that this fraction contained high copy numbers of the SINV-1 genome. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the SINV-1 purified fraction revealed three major and one minor protein bands. The protein bands were labeled VP1 (40.8+/-1.4 kDa), VP2 (35.7+/-2.8 kDa), VP3 (25.2+/-1.8 kDa), and VP4 (22.2+/-2.5 kDa) based on mass. N-terminal sequence was acquired successfully for VP1, VP2, and VP3, but not VP4, and delineated each capsid protein within the 3'-proximal open reading frame of SINV-1. Positional organization of the viral proteins within the SINV-1 structural polyprotein was consistent with dicistroviruses (when based on sequence similarity). Blastp analysis of SINV-1 VP1, VP2, and VP3 revealed significant identity with corresponding structural capsid proteins of positive-strand RNA viruses, particularly acute bee paralysis virus (ABPV), Kashmir bee virus (KBV) and Israeli acute paralysis virus (IAPV). Amino acid residues about the scissile bonds for VP1 and VP3 were consistent with dicistroviruses and insect-infecting picorna-like viruses. N-terminal sequencing of VP2 also established that translation initiation of the SINV-1 structural polyprotein was mediated by an internal ribosomal entry site and is AUG-independent.
USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, FL 32608, USA. svalles@gainesville.usda.ufl.edu
Steven M
SM
Valles
Yoshifumi
Y
Hashimoto
D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D023061:Gene Order; D008970:Molecular Weight; D016366:Open Reading Frames; D010849:Picornaviridae / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure; D012367:RNA, Viral / Q000235:genetics; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D015678:Viral Structural Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D014771:Virion / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure
D036022:Capsid Proteins; D012367:RNA, Viral; D015678:Viral Structural Proteins