pEMBL: A new family of single stranded plasmids

We have constructed a series of plasmids, the pEMBL family, characterized by the presence of 1) the bla gene as selectable marker, 2) a short segment coding for the β-peptide of β-galactosidase and containing a multiple cloning sites polylinker, 3) the intragenic region of phage Fl.pEMBL plasmids have the property of being encapsidated as single stranded DNA, upon superinfection with phage Fl. These vectors have been used successfully for DNA sequencing with the dideoxy-method, and can be used for any other purpose for which M13 derivatives are used. However, the pEMBL plasmids have the advantage of being smaller than Ml3 vectors, and the purification of the DNA is simpler. In addition, and most importantly, long inserts have a higher stability in pEMBL plasmids than Ml3 vectors.