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Fig. 8. Stau259 and Stau252 isoforms are associated with
ribosomes. (A) Cytoplasmic extracts from rat cortical neurons in culture were
prepared, placed on a 20-60% discontinuous sucrose gradient and centrifuged at
175,000 g for 3 hours. Fractions were recovered and analyzed
by western blotting with monoclonal anti-Stau2 (Stau2), anti-L7a (L7a) and
anti-calnexin (CNX) antibodies. The same results were obtained from three
independent experiments. R, ribosomes. (B) Cytoplasmic extracts from neurons
in culture were treated with 25 mM EDTA to dissociate ribosomal subunits and
centrifuged at 250,000 g for 4 hours on a 10-40% continuous
sucrose gradient. Fractions were recovered and analyzed by western blotting
with monoclonal anti-Stau2 antibodies. Similar results were obtained with
rabbit polyclonal anti-Stau2 antibodies (data not shown). The position of the
40S and 60S ribosomal subunits was determined with a spectrophotometer set at
254 nm.