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Fig. 2. Biochemical detection of SgP-CgA-GFP in sucrose density gradient fractions
and in the secreted medium from PC12 cells. (A) Subcellular localization of
SgP-CgA-GFP in PC12 cells. Postnuclear supernatants prepared from
[3H]-L-norepinephrine-labeled PC12 cells transiently expressing
SgP-CgA-GFP were centrifuged to equilibrium on sucrose density gradients.
Fractions were assayed for sucrose concentration, GFP fluorescence and
scintillation counting. (B) Immunochemical detection of the SgP-CgA-GFP
chimera in sucrose density gradient fractions. Gradient fractions were
concentrated using SepPak C-18 cartridges and processed for immunoblot using
an anti-GFP antibody. (C) Immunochemical detection of stimulated release of
SgP-CgA-GFP or proANF-GFP. Regulated secretion from SgP-CgA-GFP- or
proANF-GFP-expressing PC12 cells was triggered by 2 mM BaCl2.
Extracellular media were concentrated using C-18 SepPak cartridges and
processed for immunoblot using an anti-GFP antibody. Immunoreactivity was
visualized by chemiluminescence.