THE NUCLEOTIDE-SEQUENCE, STRUCTURE, AND PRELIMINARY STUDIES ON THE TRANSCRIPTIONAL REGULATION OF THE BOVINE ALPHA-SKELETAL-ACTIN GENE

The promoters of mammalian striated muscle actin genes contain binding sites for a number of transcription factors. Examples are the CArG bo xes, which bind a protein identical to or related to serum response fa ctor (SRF), E boxes, which bind myogenic determination factors such as MyoD and myogenin, and -CCGCCC-moths, which bind the transcription fa ctor Sp1. To date, the only mammalian sequences isolated and analyzed are from rodent and human. We have now isolated and sequenced the bovi ne gene encoding a skeletal actin, including almost 3 kb of 5'-flankin g region. When compared to the human and rodent genes (the only ones p reviously cloned and for which 5'-flanking sequences to only approxima tely -750 are known), there was the expected conservation in the codin g region. A comparison of the promoter regions indicated that the bovi ne gene has three CArG boxes in the 5'-flanking region in positions id entical to those in other species. The bovine proximal promoter is uni que from those of human and rodent in that it has only one E box in th e vicinity of the TATA box, near -350, whereas the other mammals have three. Far upstream sequences reveal clusters of E boxes near -2,500 a nd -1,500. A minimal promoter element, to -297, which has no E boxes, is sufficient to activate transcription in myotubes derived from rat L 6 and mouse C2C12 myoblasts.