The Murine Polyomavirus MicroRNA Locus Is Required To Promote Viruria during the Acute Phase of Infection.

Polyomaviruses (PyVs) can cause serious disease in immunosuppressed hosts. Several pathogenic PyVs encode microRNAs (miRNAs), small RNAs that regulate gene expression via RNA silencing. Despite recent advances in understanding the activities of PyV miRNAs, the biological functions of PyV miRNAs during infections are mostly unknown.

Overexpression of murine phosphatidylinositol 4-phosphate 5-kinase type Ibeta disrupts a phosphatidylinositol 4,5 bisphosphate regulated endosomal pathway.

The type I phosphatidylinositol 4-phosphate 5-kinases (PI4P5K) phosphorylate phosphatidylinositol 4-phosphate [PI(4)P] to produce phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. PI(4,5)P2 has been implicated in signal transduction, receptor mediated endocytosis, vesicle trafficking, cytoskeletal structure, and membrane ruffling. However, the specific type I enzymes associated with the production of PI(4,5)P2 for the specific cellular processes have not been rigorously defined.