FIG. 6.

Southern transfer analyses of the stability of the RSVP vector. (A) The probe was prepared from RCASBP(A) as a 1.2-kb EcoRI fragment to provide equal opportunity to hybridize to EcoRI fragments that contained (or had lost) the cassette. EcoRI recognition sites are indicated (E) (not to scale). (B) Detection of the cassette insert in the genomic DNA derived from cells infected with the RSVP(A)B and RSVP(A)Z vectors. Genomic DNA was digested with EcoRI, resolved in an agarose gel, transferred onto a nitrocellulose membrane, and hybridized with ³²P-labeled DNA prepared from the 1.2-kb EcoRI fragment of RCASBP(A). The larger band represents a 2.4-kb EcoRI fragment containing the insert, whereas the smaller band represent a 1.2-kb EcoRI fragment lacking the insert.