Analysis of gene expression regulated by Drosophila melanogaster Tis11

In mammalian cells, AU-rich elements (AREs) are well known regulatory sequences located in the 3' untranslated region (UTR) of many short-lived mRNAs that suppress gene expression at the posttranscriptional level. Tis11, a zinc finger RNA-binding protein homologous to mammalian tristetraprolin, targets ARE-containing reporter mRNAs for rapid degradation in SL2 cells. To identify Drosophila mRNA targets of Tis11, we performed genome-wide expression profiling after dsRNA-mediated depletion of endogenous Tis11 in SL2 cells. Furthermore, we studied the involvement of Tis11 in regulating the Drosophila immune response by profiling mRNA expression after LPS treatment, in the presence or absence of Tis11. SL2 cells were treated with either dsRNA against Tis11 or dsRNA against GFP (control). After 4 days of treatment with 12.5 microgram dsRNA / ml medium, total RNA was extracted and hybridized to Drosophila Genome 2.0 Arrays (Affymetrix, Cat. No. 900531). Where indicated, cells were treated with lipopolysaccharide (LPS, Sigma, O55:B5) at a concentration of 10 microgram / ml for 4 hours before lysis. All experiments were performed in 3 biological replicates.