Figure 1. Alignment of inferred N-terminal amino acid sequences of 33 alleles of emm1. The region shown represents amino acids 27 through 110 (GenBank accession number X07860). Six of the emm1 alleles were identified in this study, several were described previously (1,5,12), and others were from ongoing analysis of emm1 in M1 strains from global sources. Amino acid residues identical to those encoded by emm1.0 are represented by periods.

Figure 2. Variation in the sic gene and Sic protein identified in M1 group A Streptococcus isolates characterized in the study. The figure is a compilation of variations found in the 15 distinct sic alleles in the sample. The numbers at the top of the figure refer to the nucleotide sequence position of a sic allele described in reference 6. Single-letter amino acid abbreviations are used. SRR, amino-terminal short repeat region; Roman numeral, short repeats I-V which recur in SRR; R2 and R3, tandem repeats; MGAS strain, Musser Group A Streptococcus strain number; X, presence of polymorphism.

Figure 3. Representative IS1548 RFLP fingerprint patterns of M1 isolates. Panel A is a lane map showing results from analysis of three serotype M3 control isolates and four M1 isolates with different sic alleles. Lane 1, MGAS5892; lane 2, MGAS6004; lane 3, MGAS6005; lane 4, MGAS5997; lane 5, MGAS5999; lane 6, MGAS6003; lane 7, MGAS6006. kb, 1-kb DNA ladder. Panel B is a lane map showing results from analysis of eleven M1 isolates with eight different sic alleles. Lane 1, MGAS6201; lane 2, MGAS6249; lane 3, MGAS6251; lane 4, MGAS6254; lane 5, MGAS6262; lane 6, MGAS6264; lane 7, MGAS6272; lane 8, MGAS6281; lane 9, MGAS6293; lane 10, MGAS6294; lane 11, MGAS6299. kb, 1-kb DNA ladder. Panel C is a lane map showing results from analysis of four speA-positive and seven speA-negative M1 isolates. Lane 1, MGAS2350, lane 2, MGAS2221, lane 3, MGAS2139, lane 4, MGAS1272, lane 5, MGAS6708, lane 6, MGAS1653, lane 7, MGAS1642, lane 8, MGAS1632, lane 9, MGAS570, lane 10, MGAS326, lane 11, MGAS279. kb, 1-kb DNA ladder.

Figure 4. Polymorphism identified in the direct repeat (DR) region of serotype M1 group A Streptococcus. The data were generated by automated DNA sequencing of polymerase chain reaction products obtained with the oligonucleotide primers DR003 and DR004 described in the text. (A) The 36-bp sequences of the two related DR and DR' elements. Multiple copies of the DR element present in different M1 isolates all had the identical sequence. (B) The 29-bp or 30-bp sequences of the 10 distinct spacer regions identified in the analysis. (C) Arrangement of the DR elements and spacer sequences in nine distinct DR allelic variants. The DR types were given arbitrary designations based in part on the number of DR elements present. Open or cross-hatched rectangles represent copies of the DR or DR' elements; arrows represent copies of the spacer region sequences connecting the DR elements. The numbers above the spacer region sequences refer to the spacers designated in part B of the figure.