Alignment of the non-coding regions between rep and replication-associated genes of pBMB165, pBT9727, pXO2 and pAW63. The shaded letters indicate identical nucleotides. Arrows on the nucleotide sequences represent the iterons sequences. The conserved regions of high A+T content are underlined. The putative ribosome binding site (RBS) of rep is also highlighted in boldface.