FIG. 5.

Northern hybridization analysis of the c2 ori fragments that did not support plasmid replication. The fragments were recloned into a plasmid (pFX3) that contains an origin of replication for gram-positive bacteria. Twenty-microgram portions of total RNA from L. lactis strain MG1363 harboring the plasmids were electrophoresed on acrylamide gels, blot transferred, and then probed with different PCR products and detected by the ECL system. The migration positions of two marker bands (280 and 155 nt) are indicated on the left. Each lane is labeled with the designation of the plasmid construct (see Fig. 1 and 2 for schematic representations of the constructs). The following PCR-generated probes were used: lane pFX3-214, template pLP214 and primers ori11 and ori12; lane pFX3-213, template pFX3-213 and primers ori4 and M13 Rev; lanes pFX3-215, pFX3-223, pFX3-218, pFX3-219, pFX3-220, pFX3-221, pFX3-222, pFX3, pFX3-203, pFX3-205, pFX3-206, pFX3-207, pFX3-216, pFX3-208, and pFX3-204, template pLP206 and primers ori1 and ori7.