E-SMDB-3537 - Transcription profiling of Drosophila melanogaster adults and embryos
Released on 11 November 2006, last updated on 12 October 2011
See describtion in Gerber AP. et al (2005). Biochemical purification: Five grams of adult flies or 2.5 g of embryos were used in each affinity purification. Flies or embryos were suspended in 15 ml of buffer B (buffer A plus 1.5 mM dithiothreitol [DTT], 1 mM phenylmethylsulfonylfluoride [PMSF], 0.5 5g/ml leupeptin, 0.8 5g/ml pepstatin, 20 U/ml DNase I, 100 U/ml RNasin [Promega], and 0.2 mg/ml heparin) in a mortar filled with liquid nitrogen and ground with a pestle to a fine powder. The powder was transferred to a glass-dounce, thawed and dounced until the pestle reached the bottom. The suspension was centrifuged twice at 40C and 10,000 g for 10 min. The fat layer on top was aspirated off after each centrifugation. Cleared extract (12.5 ml) was incubated with 600 5l of a slurry (50% [v/v]) of IgG-agarose beads (Sigma) for 90 min at 4C. The beads were washed once with buffer B for 15 min at 4C, and three times for 15 min at 4C with buffer C (20 mM TrisHCl [pH 8.0], 150 mM NaCl, 1 mM EDTA [pH 8.0], 10% glycerol, 0.01% NP-40, 1 mM DTT, 10 U/ml RNasin). PumHD was released from beads by incubation with 150 Units of AcTEV protease (Invitrogen) for 2 hr at room temperature (RT). RNA was isolated from extracts and from the TEV eluates with TRIZOL reagent (Invitrogen) followed by RNeasy Mini-Kit (Qiagen) purification according to the manufacturer's instructions. Microarray analysis: A pool of four control cDNAs (2 ng of each flp, gal4, lacZ and -Gal) was added to each RNA sample prior to labeling as controls for the labeling procedure. Total RNA (12 5g) derived from the extract and 300 ng or 30% of the affinity-isolated RNA were labeled with Cy3 and Cy5 fluorescent dyes, respectively, following cDNA synthesis with amino-allyl dUTP in addition to the four natural dNTPs using a 1:1 mixture of oligo(dT) and random nonamer primers. The Cy3- and Cy5-labeled cDNA samples were mixed and hybridized to Drosophila DNA microarrays.
transcription profiling by array, RNA IP, all pairs