The yybP-ykoY RNA motif was originally discovered in a large-scale genomic screen for conserved riboswitch-like motifs in intergenic regions of various microbial species [15096624]. Representatives of this family were found upstream of related families of protein genes in many bacteria, including the yybP and ykoY genes in Bacillus subtilis. The specific functions of these proteins are unknown, but this structured RNA element may be involved in their genetic regulation as a riboswitch. An ortholog of ykoY in Escherichia coli, the ygjT gene, is also preceded by similar RNA motif and was known to be induced by extreme alkaline conditions [2108134]. more

In a large-scale screen in E. coli, a small RNA (named a sraF gene) was detected upstream of the ygjT gene, which corresponds to the yybP-ykoY element [11448770]. The promoter of the sraF gene was found to be active in vitro and in vivo resulting in two transcripts of 110 and 189 nt. The secondary transcription termination-like structure located ~110 nt downstream of the small RNA start was active as a terminator in vitro. It was also shown that the sraF RNA is almost exclusively present during cold shock [11448770].