Discovery of bacterial sRNAs by high-throughput sequencing.

sRNA-Seq is an unbiased method that allows for the discovery of small noncoding RNAs in bacterial transcriptomes through direct cloning and massively parallel sequencing by synthesis. Small bacterial transcripts are enriched from a total RNA preparation and modified with 5' and 3' linkers that allow for downstream amplification and sequencing. This protocol includes a treatment that depletes small RNA fractions of tRNAs and 5S rRNA, thereby enriching the starting pool for non-tRNA/rRNA sequences. This protocol can be readily modified to target different RNA species for depletion or to change the size range of RNAs to be sequenced. Thus, sRNA-Seq represents a comprehensive, versatile cloning protocol that may be applicable to the cloning of small RNAs of any size range from any organisms.