A cDNA cloning vector that permits expression of cDNA inserts in mammalian cells.

A plasmid vector for cloning cDNAs in Escherichia coli is described; the same vector also promotes expression of the cDNA segment in mammalian cells, and it is confirmed that the alpha-globin transcript produced in transfected cells is initiated correctly, spliced at either of the two introns, and polyadenylated either at the site coded in the c DNA segment or at the distal SV40polyadenylation signal.