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. Author manuscript; available in PMC: 2016 Jan 31.
Published in final edited form as: Virology. 2014 Dec 30;476:240–248. doi: 10.1016/j.virol.2014.12.019

Fig. 1.

Fig. 1

Secreted gp120-sfGFP is expressed in human cells and acquires N-linked glycans. (A) Human codon optimized gp120, including the native signal sequence, was fused upstream to sfGFP to create gp120-sfGFP. The control SS-sfGFP construct contains the bovine prolactin signal sequence (SS) followed by sfGFP. (B) Representative image of transiently transfected U-2 OS cell expressing gp120-sfGFP, scale bar = 10 μm. Media (M) and cell lysates (C) were collected and examined by immunoblotting with anti-GFP antibody from U-2 OS transiently transfected with (C) gp120-sfGFP and SS-sfGFP or (D) gp120-sfGFP with or without 5 μg/mL tunicamycin (Tm). Shift to lower molecular weight indicates non-glycosylated (-CHO) gp120-sfGFP. (E) To determine approximate concentration of gp120-sfGFP collected, serial dilutions of purified sfGFP samples of known concentration (lanes 3–7) were compared with PNGase treated gp120-sfGFP (lane 2) by immunoblotting with anti-GFP antibody.