Evidence that the Functional β-Actin Gene Is Single Copy in Most Mice and Is Associated with 5′ Sequences Capable of Conferring Serum- and Cycloheximide-Dependent Regulation

Abstract

Hybridization to synthetic oligonucleotides representing conserved regions in the promoter and first intron of several vertebrate β-actin genes was used to discriminate between what appears to be a single functional β-actin gene and numerous pseudogenes in the mouse genome. Sequences derived from the 5′ end of this gene were shown to confer serum-inducible expression upon a heterologous reporter gene when transfected into mouse fibroblasts. Moreover, these sequences rendered reporter gene expression superinducible by a combination of serum and cycloheximide. These experiments indicate that the 5′ end of the mouse β-actin gene contains sequence elements which mediate the stimulatory effects of serum growth factors and which are responsive to both positive and negative regulators of gene expression.