Restriction sites are marked : BamHI (B), HindIII (H), KpnI (K), PstI (P), EcoRI (RI), SalI (Sa), SmaI (Sm), SstI (Ss), XbaI (X), Xmal (Xm). The figure is not drawn to scale. The vector is available in two versions, with either a Bam or EcoRI site for insertion of an open reading frame.