FIGURE 5.

gal-1 modulates the oligomeric state of NiV-F and NiV-G. A, Association of NiV-F and NiV-G. Extracts of 293T cells expressing NiV-F and NiV-G (F + G), or NiV-F or NiV-G alone, were immunoprecipitated with anti-F peptide or anti-G peptide antisera. Precipitated proteins were detected with anti-AU1 to detect both NiV-F and NiV-G. Anti-F and anti-G coimmunoprecipitated NiV-G and NiV-F, respectively (lanes 1 and 2). When NiV-F and NiV-G were expressed alone, anti-F and anti-G precipitated only the relevant glycoproteins (lanes 3–6). No precipitated protein was seen in cells transfected with plasmid alone (lanes 7 and 8). B, gal-1 modulates oligomerization of NiV-F and NiV-G. gal-1 was added to 293T cells expressing NiV-F or NiV-G. Cell surface proteins were cross-linked using membrane impermeant cross-linkers (BS³ for NiV-F and sulfo-GMBS (SG) for NiV-G), and NiV-F and NiV-G were detected with anti-AU1. Uncleaved NiV-F monomer (F₀) and the estimated NiV-F trimer (3×) are indicated. Molecular mass markers are shown. Molecular mass estimates >180 kDa are not precise, but for NiV-G, the progressive laddering pattern suggests that monomers (1×), dimers (2×), trimers (3×), and tetramers (4×) are formed. M, 10 mM monomeric N-Gal-1, does not enhance oligomerization.