DO11.10 x TCR-Calpha-/- T cells stimulated under Th2 conditions for 6 days were centrifuged over Histopaque 1083 (Sigma) to remove dead cells, washed and rested for 20 min at 37C in complete media with 0.1 mg/ml cycloheximide (CHX, Sigma) added for the final 10 min. Restimulated cells were activated with 10 ug/ml plate-bound I-Ad/ova complexes for 3 hrs. Cells were washed with ice-cold PBS/CHX and resuspended in polysome extraction buffer [30 mM HEPES (pH 7.4), 15 mM MgCl2, 0.3 M NaCl, 1% Triton X-100, 0.1 mg/ml CHX, 1 mg/ml heparin, 500 U/ml SUPERase-In RNAse inhibitors (Ambion, Austin, TX), 1x Complete EDTA-free protease inhibitor cocktail (Roche, Indianapolis, IN)]. After incubation on ice for 25 min, nuclei and debris were removed by centrifuging and the cleared supernatants transferred to fresh tubes. 1.5 ml of each extract (from 3 x 10exp8 T cells) were layered on a 37.5 ml 10-50% sucrose gradient prepared in SW28 ultraclear centrifuge tubes (Beckman Coulter, Fullerton, CA) using the salts described above, but without detergent, RNAsin or protease inhibitors. After centrifugation for 220 min at 28,000 rpm (average RCF = 103,745), fractions were isolated using an ISCO density gradient fractionator (Lincoln, NE) by pumping 60% sucrose into the bottom of the tube and collecting the displaced volumes into acid phenol:chloroform, with constant monitoring of ultraviolet absorbance at 254 nm. Extracted RNA was precipitated with isopropanol, washed and resuspended in distilled water. RNA from polysome associated fractions 7-12 of the gradients described above were pooled and 30-100 ug of total RNA per sample were used to template a Superscript III reverse transcription reaction (Invitrogen, Carlsbad, CA) incorporating amino-allyl dUTP (Sigma). cDNA samples were washed with distilled water on microcon-30 columns (Millipore, Billerica, MA), dried and labeled with Cy3 (primed samples) or Cy5 (restimulated samples) using CyDye reactive dye labeling kits (Amersham). Unincorporated dye was removed using QiaQuick PCR purification columns (Qiagen), labeled cDNAs were eluted in 10mM Tris, pH 8, combined and dried. Fluorescence in the Cy3 and Cy5 channels was acquired using an Axon 4000B microarray scanner and GenePix software (Axon Instruments, Union City, CA). Data were normalized using the R package Bioconductor software and lowess normalization on the pixel medians without background subtraction (Ihaka and Gentleman, 1996).
Keywords = Th2 differentiation
Keywords = translation
Keywords = polysome profile
Keywords: cell stimulation
Overall design: This experiment is composed of two arrays, treated cells vs. primary cells.
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