Rat alpha 2u globulin is encoded by a multigene family.

The hormonally responsive rat liver protein designated alpha 2u globulin is encoded by a multigene family. Southern blot hybridization analysis, and solution hybridization using a cloned alpha 2u globulin cDNA, indicate the presence of 18-20 alpha 2u globulin genes per haploid genome. In situ hybridization to rat metaphase chromosomes, using 125I-labeled alpha 2u globulin cDNA, indicates that most, and perhaps all, of the alpha 2u globulin genes are clustered on chromosome 5. Several alpha 2u globulin genes have been isolated from a rat library cloned in lambda phage. At least six of these clones appear to contain the entire alpha 2u globulin mRNA coding region. These genes are contained on different-sized restriction fragments, and are surrounded by distinct flanking sequences. Two of the six clones containing the alpha 2u globulin genes were found to have diverged greatly from the other four in the DNA sequence corresponding to the 3' untranslated region of mRNA. The implications for the hormonal control of alpha 2u globulin synthesis are discussed.