Disease relevance of L2

• Previous data have shown that the positively charged termini of BPV1 L2 are required for BPV1 infection after the binding of the virions to the cell surface [1].
• To better understand how the virus traffics across the cell, we sought to identify cellular proteins that bind to the minor capsid protein L2 [2].
• The L1 and L2 proteins of BPV-2 have been produced in Escherichia coli as beta-galactosidase fusion proteins [3].

High impact information on L2

• Mutations within the DKILK motif of L2 that did not significantly impact virion morphogenesis or binding at the cell surface prevented the L2 interaction with syntaxin 18 and disrupted BPV1 infection [2].
• The positively charged termini of L2 minor capsid protein required for bovine papillomavirus infection function separately in nuclear import and DNA binding [1].
• Interestingly, the cNLS was also the major DNA binding site of BPV1 L2 [1].
• During the papillomavirus (PV) life cycle, the L2 minor capsid protein enters the nucleus twice: in the initial phase after entry of virions into cells and in the productive phase to mediate encapsidation of the newly replicated viral genome [1].
• Animals vaccinated with L1, but not with L2, responded rapidly with production of serum neutralizing antibodies, showing that this peptide contains B-cell-specific epitopes [3].

Biological context of L2

• These data support a model in which BPV1 L2 functions as an adapter between the viral DNA via the cNLS and the Kaps via the nNLS and facilitates nuclear import of the DNA during infection [1].
• Identification of L2 open reading frame gene products of bovine papillomavirus type 1 using monoclonal antibodies [4].

Anatomical context of L2

• Hybridomas were selected and cloned (from over 700 hybridomas) on the basis of specific reactivity of supernatant fluids with BPV-1 L2 epitopes on disrupted BPV-1 particles and L2-beta-galactosidase fusion proteins by ELISA and Western blotting, and with acetone-fixed frozen sections of BPV-1-induced fibropapillomas by immunofluorescence [4].
• Four hybridoma cell lines producing monoclonal antibodies (MAbs) to bovine papillomavirus type 1 (BPV-1) L2 open reading frame (ORF) gene products have been established from mice immunized with a BPV-1 L2-beta-galactosidase fusion protein [4].

References