Figure 2.

LEC regulates U11 snRNA gene transcription. (A) Heatmap of gene expression changes after ELL RNAi in S2 cells. Shown are the genes whose expression changed 2- fold. The most changed gene on the array is Fire exit (Fie) which is up-regulated, while Su(Tpl), which encodes ELL, was the second most changed gene, and is down-regulated. (B) Fie is notable for having a snRNA gene in its first intron. The FlyBase annotation for the Fie transcript shows that the U11 snRNA gene is transcribed in the anti-sense direction relative to Fie, which could conceivably antagonize Fie expression. Yellow represents an open reading frame; gray, untranslated regions; thin lines, introns; and the non-coding transcript for U11 is shown in red. (C-D) To determine whether ELL regulates U11 or Fie, we performed quantitative RT-PCR on these two genes after RNAi of ELL using two non-overlapping regions of dsRNA, ELL-A, and ELL-B. While Fie is up-regulated after ELL RNAi (C), U11 is down-regulated (D). Expression is relative to Rp49. Error bars represent the standard deviations. (E-G) Northern blot analysis of ELL and Ice1 RNAi samples shows that U11, but not the Pol III-transcribed U6 snRNA gene, is dependent on LEC. The same Northern blot was probed with Rp49, U11, and U6 ³²P-labeled riboprobes and analyzed by phosphorimaging and quantitation with Typhoon scanner and ImageQuant software. The scan (E) and quantitations of U11 (F) and U6 (G) relative to Rp49 are shown.