RNA-affinity isolations 13 RBPs

To identify RNAs specifically associated with potential RBPs, yeast cells expressing TAP-tagged RBP or the wild-type strain BY4741 (mock control) were grown to mid-log phase in rich medium and harvested by centrifugation. RNA affinity isolations were essentially performed as described (Gerber et al. 2004 PLoS Biol.; see protocol). In brief, TAP-tagged protein were captured from cell extracts with IgG coupled agarose beads (Sigma) and released by incubation with a site-specific protease (AcTEV, Sigma). from the extract (input) and from the affinity isolates was purified with the RNeasy Mini/ Micro Kit (Qiagen). RNAs were reverse transcribed using a mixture of oligo-dT and random nonamer oligos in the presence of amino-allyl dUTP/dNTP mixture. cDNAs were fluorescently labeled and hybridized on yeast oligo microarrays over night at 42 degrees in formamide-based hybridization buffer. Antigenic peptide used in IP: TAP-tag An all pairs experiment design type is where all labeled extracts are compared to every other labeled extract.