FIG. 1.

Construction of pBSCA and pBSCAδE5 molecular clones. pK9Kb plasmid DNA was double digested with SalI and PflmI to release an 8.4-kb fragment corresponding to the complete CAEV-CO genome lacking the 3′ end of the env gene and 3′ LTR. This fragment was gel purified and then inserted into the pBSΔ plasmid DNA doubly digested with XhoI and PflmI. The isolated molecular clone corresponds to a reconstituted complete infectious proviral CAEV-CO genome (pBSCA). pBSCAδE5 was derived from the pBSCA plasmid by deletion of an 0.4-kb BamHI fragment in the envelope-coding sequence.