Figure 2.

Motif 1 is required for transcription of RpL30 and RpLP1 in vitro. (A and B) Primer extension analysis of transcripts produced from the (A) RpL30 and (B) RpLP1 promoters (−500 to ∼+50) during transcription in Drosophila embryo nuclear extracts. Transcription reactions lacking α-amanitin were performed in triplicate. The bracketed region encompasses the M1BP-dependent TSS region and a portion of the TCT motif (Parry et al. (11). The M1BP-dependent transcription start sites (TSSs) observed in vitro correspond to the TSSs detected in vivo using PRO-cap (Kwak et al.(30)). (C) Quantification of bracketed TSS region transcripts from (A and B). Error bars represent standard deviation (n = 3). Samples have been normalized to the first wt replicate for each promoter. ‘*’ Denotes an artifact band arising in the Motif 1 region following mutation.