(A) Organization of the nine vir-like CDSs (white arrows) and five adjacent CDSs that encode for either putative membrane-spanning proteins (black arrows) or non-vir CDSs (gray arrows) of wMel, R. conorii, and A. tumefaciens. Solid horizontal lines denote RT experiments that have confirmed that adjacent CDSs are expressed as part of a polycistronic transcript. Results of these RT-PCR experiments are presented in (B). Lane 1, virB3-virB4; lane 2, RT control; lane 3, virB6-WD0856; lane 4, RT control; lane 5, WD0856-WD0855; lane 6, RT control; lane 7, WD0854-WD0853; lane 8, RT control; lane 9, virB8-virB9; lane 10, RT control; lane 11, virB9-virB11; lane 12, RT control; lane 13, virB11-virD4; lane 14, RT control; lane 15, virD4-wspB; lane 16, RT control; lane 17, virB4-virB6; lane 18, RT control; lane 19, WD0855-WD0854; lane 20, RT control. Only PCRs that contain reverse transcriptase amplified the desired products. PCR primer sequences are listed in .