Dam-specific RNA-seq

To determine the transcription start site and the abundance of dam mRNA, we conducted mRNA-specific RNA-Seq experiments. Essentially two strategies were tested. First strategy: We obtained the cDNA with a specific RT-PCR in order to get the mRNA from our dam construct (see DNA-seq of DamID reporter cassette). An enrichment, in which we used a Biotinylated dam oligo and Streptavidin magnetic beads, was needed. Then, similar to SHAPE-seq, the ssDNA ligation was performed with CircLigase. The last step was the PCR reaction in order to prepare the cDNA libraries to be sequenced. Second strategy: Similar to the first one, but the specificity was introduced at the PCR, not at the RT. Thereby, busk cDNA was prepared with random hexamers. The enrichment step was not needed.