| Restriction digests of the clone give the following sizes (kb): HindIII--24.1, 17.6; EcoRI--22.0, 20.0; BamHI--24.8, 16.9; XbaI--32.7, 9.0; NotI--41.7. 
 Efficiency of phagemid recovery is approximately 20%.  Plasmid pCRE1 may be a low level contaminant, but is easily distinguished from pMGU DNA. 
 To prepare phagemid from lambdaMGU2, grow recombinants on a RecA- host expressing the Cre protein (E. coli 1046[pCRE1], ATCC 77368) and select for ampicillin resistance. The pMGU product is 4.185 kb. 
 Vector useful for constructing cDNA libraries.  Permits positive selection for inserts using the Spi- phenotype, and excision of phagemid by lox/cre site-specific recombination. 
 To enable the positive selection of inserts, the library should be plated on a P2 lysogen such as Escherichia coli Q359 (ATCC 47019). 
 Inserts can be amplified using the following primers flanking the BamHI cloning site:  upstream 5'-AAGAGGCAGAACTGGCAG-3' and downstream 5'-ATCGATGCATAGCGATTC-3'. 
 The order of the major features in the cloning region of the lambda vector is:  lambda J - SmaI - SalI - loxP - EcoRI - M13 ori - ampR - pMB1 ori - HindIII - 3'gam/BamHI/5'gam - XhoI - loxP - SalI - lambda N. |