ISOLATION AND CHARACTERIZATION OF THE FUNCTIONAL GENE ENCODING BOVINECYTOCHROME-C-OXIDASE SUBUNIT-IV

The structure and expression of the gene (COX4) encoding bovine cytoch rome c oxidase subunit IV (COX IV) was studied in order to identify co nserved DNA sequence elements involved in the control of mammalian nuc lear respiratory genes. The functional bovine COX4 gene consists of fi ve exons and four introns and is similar in organization to rat and mo use COX4. The domain encoded by exon 3 is the most highly conserved am ong the three species, suggesting it may encode a key functional domai n of COX IV. Transcription of bovine COX4 begins at multiple sites, as has been seen previously for rat and mouse COX4 and other TATA-less g enes. Comparative analysis of bovine, rat and mouse COX4 promoters ide ntified multiple binding sites for the regulatory proteins Sp1 and GAB P (NRF-2). The varied arrangements of multiple Sp1 and GABP sites in m ammalian COX4 promoters suggests flexibility in the positioning of reg ulatory factors in controlling COX4 expression.