(A) Summary of the DNA sequences in the erm(41) regions of 10 M. abscessus isolates: MC719 (GenBank accession no. EU177504), MC720 (GenBank accession no. EU590124), MC723 (GenBank accession no. EU590125), MC724 (GenBank accession no. EU590126), MC725 (GenBank accession no. EU590127), MC1082 (GenBank accession no. EU590128), MAB30 (GenBank accession no. EU590129), MC879 (GenBank accession no. EU872494), MC958 (GenBank accession no. EU872495), and MC1028 (GenBank accession no. EU872496). The reference sequence was that derived from M. abscessus isolate MC719, and the base numbering is from the first base of the erm(41) ORF. The base changes are shown above the sequence, with the resulting amino acid change (when appropriate); the boxes show the two sequence differences of the susceptible isolates MAB30 and MC1028, relative to the reference sequence. The line immediately underneath the sequence represents the deletions in the erm(41) allele of susceptible isolate MC1082. The thick lines above the sequence represent the three most stable predicted RNA helix loop structures in the leader region and the first 100 bases of the erm(41) transcript. Experimentally determined TSS and putative −10 and −35 elements are shown. (B) ClustalW DNA alignment of the promoter, leader region, and first three codons of erm(41) with the equivalent region of the erm(37) gene of M. tuberculosis (derived from GenBank accession no. NC_000962, bases 2231617 to 2231688). The TSS of erm(41) is indicated, and identical bases are shown boxed and shaded; the amino acid residues for the predicted N termini of the Erm(41) and Erm(37) polypeptides are shown above and below the DNA alignment, respectively.