GENOMIC SEQUENCE, STRUCTURAL ORGANIZATION AND EVOLUTIONARY CONSERVATION OF THE 13.2-KDA SUBUNIT OF RAT NADH-UBIQUINONE OXIDOREDUCTASE

The 13.2-kDa subunit of NADH:ubiquinone oxidoreductase has been shown to be an integral part of the bovine iron-sulfur (IF) part of the prot ein. This subunit has been shown to interact with at least two other p rotein subunits of the IP fragment. The amino acid (aa) sequence of th is subunit, determined from an acid extract of rat heart was used to g enerate an oligodeoxyribonucleotide probe which allowed isolation of a cDNA coding for the rat homologue of 13.2-kDa IP. The cDNA was used a s a probe of a rat genomic DNA library and two clones were isolated, o ne of which contained the entire coding region for 13.2-kDa IP. Southe rn analysis indicates that the IP13 sequence exists as a single copy g ene. The sequence of the genomic clone contains one intron and promote r elements including a TATAAA region. The 5' flank region has several potential regulatory sites, most notably regions similar to the nuclea r respiratory factor 1 (NRF-1) motif, found in other genes which code for mitochondrial proteins [Evans and Scarpulla, Genes Dev. 4 (1990) 1 023-1034], The core domain of the deduced rat aa sequence has a high d egree of identity with the mouse and cow homologues of this protein. T he high degree of conservation of this protein indicates that the prot ein is essential for the function of complex I.