Cloning of alpha 2u globulin cDNA using a high efficiency technique for the cloning of trace messenger RNAs.

An extremely high-efficiency technique is described for cloning double-stranded (ds) cDNAs in Escherichia coli. The method, which uses two synthetic oligonucleotide linkers rather than one, results in approx. 200--500 recombinant clones per ng of ds cDNA. This technique was used to clone a cDNA comprising 95% of the full length of the mRNA of alpha 2u globulin, a male rat liver protein, which represents approx. 1% of hepatic messenger RNA. The cloned probe was applied to study the complex hormone controls of alpha 2u globulin mRNA in male and female rats.