Plasmids pEMBLY: new single-stranded shuttle vectors for the recovery and analysis of yeast DNA sequences

We describe the construction and properties of pEMBLY plasmids. They belong to a new family of yeast shuttle vectors which are derived from plasmid vector pEMBL9 and offer the following improvement: relatively small size; large number of cloning sites; screening for insert-containing plasmids on indicator plates; different combinations of genes which complement auxotrophic deficiencies and sequences that support DNA replication in Saccharomyces cerevisiae; and ability to isolate the plasmid DNA in single-stranded (ss) form. The yeast S. cerevisiae can be efficiently transformed by these plasmids in both the ss and double-stranded (ds) forms. Finally, the presence of the phage f1 intergenic region allows one to obtain the cloned sequences in the ss form upon infection with the wild-type ss phage [Dotto et al., Virology 114 (1981) 463-473].