Intergenic regions of omp7 to AM1225 were analyzed by RT-PCR. A. Diagrammatic representation of the AM1225-omp6 operon with AM1225, omp10, omp9, omp8, omp7 and omp6 and intergenic regions. Location of primer pairs (AB1556-AB1591), (AB1592-AB1581), (AB1582-AB1569), and (AB1655-AB1595) designed for PCR amplification of omp7-8, omp8-9,omp9-10 and omp10-AM1225 intergenic regions using cDNA from ISE6 cells infected with A. marginale wild-type. B. Agarose gel analysis of amplicons connecting intergenic regions from omp7 through AM1225 (lanes 2, 5, 8, and 11). DNA was used as positive control (lanes 4, 7, 10, and 13). cDNAs from reactions with no reverse transcriptase were used as negative controls (lanes 3, 6, 9 and 12). 100 bp/1Kb DNA ladder (lane 1).