mRNA expression of pap31 in B. henselae (A) and of recombinant pap31 in E. coli M15(pREP4) (B). The amplified PCR fragment from B. henselae is 535 bp long, and that from E. coli is 291 bp long. MW, 100-bp molecular weight standard. (A) pap31 expression in B. henselae. Lane 1, RNA-PCR; lane 2, negative control; lane 3, positive control; lane 4, RT-PCR. (B) pap31 expression in E. coli. Lanes 1 to 4, RNA-PCR; lanes 5 to 8, RT-PCR. Lanes 1 and 5, E. coli M15(pREP4); lanes 2 and 6, E. coli M15(pREP4) with pQE70; lanes 3 and 7, E. coli M15 pap31 uninduced; lanes 4 and 8, E. coli M15 pap31 induced.