Moreover, we searched for conserved unknown motifs using MEME (http://meme.sdsc.edu/meme4_6_1/intro.html) and used relaxed regular expressions (i.e. pattern matching) over all Smr9C homologs promoters. This studies revealed the presence of 30 bp long region very conserved between positions -40 and -75, conserved MEME motif, (Figure 5). This sequence was present in all but one of the smrC9 homologs found, but no significant similarity to known transcription factor binding sites matrices could be established. Most of the members of the αr9 family are trans-encoded sRNAs transcribed from independent promoters in chromosomal IGRs. Exceptions are the cis-encoded antisense Smr9C homologs of "A. tumefaciens" and "B. microti", which are located in the opposite strand of annotated genes, partially overlapping ORFs. Most of the neighboring genes of the seed alignment’s members were not annotated and thus were further manually curated. The predicted protein products of these overlapping ORFs could not be assigned to any functional category on the basis of the amino acid sequence homology. However, the genomic regions of almost all αr9 sRNAs exhibited a great degree of conservation including the sRNA-coding sequence and the upstream and downstream genes which have been predicted to code for a prolyl-tRNA syntethase (proS) and a transmembrane protein, respectively. Partial synteny of the αr9 genomic regions was observed in a few cases such as, "S. medicae" where instead of a "proS" gene an FAD-dependent pyridine nucleotide-disulfide oxidoreductase encoding gene was found upstream of the αr9 locus, and "Mesorhizobium loti" where no transmembrane coding gene was recognizable downstream of the sRNA gene. A special case is the "Brucella" group, where primary automatic annotation over their genomes identified ORFs smaller than 30 aa overlapping with the predicted αr9 sRNA in the same strand. These predicted ORFs, neither show any similarity with database entries nor any motif or signatures when searched against family and motif databases such as Interpro, PFAM or Smart, and thus, are considered here as missannotations not registered in the genomic context graph.