Influenza A virus NP protein expressed in insect cells by a recombinant baculovirus is associated with a protein kinase activity and possesses single-stranded RNA binding activity.
Influenza A virus NP protein, the phosphoprotein associated with viral RNA in ribonucleoprotein (RNP) complexes, has been expressed at high levels (approximately 100 mg/liter cells) in insect (Sf9) cells by a baculovirus recombinant, and was localized almost entirely in the nuclei of these cells. NP was purified by immuno-affinity chromatography, and purified NP was shown to autophosphorylate and to phosphorylate casein in a cAMP-independent reaction. Furthermore, purified NP was able to bind to ssRNA as demonstrated by a mobility shift of ssRNA in non-denaturing gels. The binding of NP to ssRNA caused a diminution of its kinase activity in proportion to binding.
Galarza
J M
JM
Department of Cellular, Viral and Molecular Biology, University of Utah School of Medicine, Salt Lake City 84132.
Sowa
A
A
Hill
V M
VM
Skorko
R
R
Summers
D F
DF
D000818:Animals; D016367:Baculoviridae / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005822:Genetic Vectors; D009980:Influenza A virus / Q000235:genetics / Q000378:metabolism*; D009036:Moths; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D014758:Viral Core Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D012367:RNA, Viral; D014758:Viral Core Proteins; D011494:Protein Kinases