Related Experiment Video
Updated: Aug 17, 2026

Assaying for Inorganic Polyphosphate in Bacteria
Published on: January 21, 2019
Phosphate cycling on the basic protein of Plodia interpunctella granulosis virus
1Division of Biology, Kansas State University, Manhattan 66506.
Abstract:
The presence of infected cell-specific phosphoproteins was investigated in Plodia interpunctella granulosis virus (PiGV)-infected fat body using [32P]orthophosphoric acid labeling. One infected cell-specific phosphoprotein had a mobility similar to that of the basic protein (VP12) of PiGV. Further analysis, using immunoblotting and acid-urea gel analysis of infected fat body, confirmed that this phosphoprotein was VP12. However we did not detect phosphorylated VP12 in 32P-labeled nucleocapsids. Phosphoamino acid analysis of 32P-labeled VP12 revealed that phosphoserine was present in the basic protein. Since VP12 is phosphorylated in the infected cell, but not in the nucleocapsid, it appears that dephosphorylation of VP12 is a critical event in the life cycle of the virus. We therefore assayed virus nucleocapsids and infected fat body for the presence of phosphatase activity. Phosphatase activity was not detected in the virus, but the infected fat body had more activity than uninfected fat body. A model for nucleocapsid assembly and uncoating is presented which takes into account the phosphorylation state of VP12, the role of Zn2+ in the nucleocapsid, and the role of the capsid-associated kinase.
More Related Videos
Related Concept Videos
Lytic Cycle of Bacteriophages
Lysogenic Cycle of Bacteriophages
Bacterial Phylum Tenericutes
Viral Replication: Lytic Cycle
Viral Replication: Lysogenic Cycle
DNA Bacteriophages

