Interaction between nucleocapsid protein (NP) and phosphoprotein (P) of human parainfluenza virus type 2: one of the two NP binding sites on P is essential for granule formation.
The paramyxovirus phospho- (P) and nucleocapsid (NP) proteins are involved in transcription and replication of the viral genome. To study the interaction between NP and P proteins, we established HeLa cell lines that constitutively expressed the NP and/or P proteins of human parainfluenza virus type 2 (hPIV-2). Co-immunoprecipitation assays revealed that the NP and P proteins can form complexes in HeLa cells expressing both proteins (HeLa-NP+P cells) and in mixed cell lysates of HeLa-NP and HeLa-P cells. Deletion mutant analysis of the P protein was performed to identify the regions of P protein that interact with NP protein. The results indicate that two independent NP-binding sites exist on P protein: one is located in the N-terminal part of the protein, aa 1-47, and the other in the C-terminal part, aa 357-395. In addition, cells co-expressing NP and P proteins with N-terminal deletions showed immunofluorescence staining patterns (granular pattern) similar to those found in hPIV-2-infected cells. However, cells co-expressing NP and P proteins with C-terminal deletions showed a different immunofluorescence staining pattern (diffuse pattern), indicating that the C-terminal region is required for granule formation.
Nishio
M
M
Department of Microbiology, Mie University School of Medicine, Tsu-Shi, Japan. nishio@doc.medic.mie-u.ac.jp
Tsurudome
M
M
Kawano
M
M
Watanabe
N
N
Ohgimoto
S
S
Ito
M
M
Komada
H
H
Ito
Y
Y
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D001665:Binding Sites; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D019251:Nucleocapsid / Q000235:genetics / Q000378:metabolism*; D010223:Parainfluenza Virus 2, Human / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D010750:Phosphoproteins; D014764:Viral Proteins