Restriction digests of the clone give the following sizes (kb): PvuI--2.6, 1.8, 1.4; EcoRI--3.3, 2.5; HindIII--4.5, 1.3; BglII--5.8; ClaI--5.8. The plasmid contains the following restriction sites (bp from 0): NotI--0; EcoRI--9, 3272; SacI--1593; PvuI--1842, 3197, 4987; ClaI--1981; XhoI--2005; BglII--2028; SphI--3153, 3356; NsiI--3155; HindIII--2040, 3368; DrdI--3829, 5700; BsaI--4687. Expression vector containing two lacZalpha-based multiple cloning sites, with the second containing an amber mutation and being flanked by a mouse metallothionein I promoter at one end and splicing and polyadenylation signals at the other. The first site was designed for insertion of a marker selectable in mammalian cells, and the second for the sequence to be expressed. Both sites permit detection of inserts by alpha complementation, with discrimination between the two provided by the amber mutation in the second lacZ. |