Characterization of transcriptional control elements of the murine cytochrome c oxidase subunit IV gene

Robert Stuart Carter, University of Pennsylvania


The mouse cytochrome c oxidase subunit IV (COXIV) gene was studied in an effort to determine the mechanisms by which the expression of nuclear encoded mitochodrial respiratory proteins is coordinated. cDNA for mouse COXIV was isolated by screening mouse liver and kidney cDNA libraries with a bovine COXIV cDNA probe. The 679 nucleotide nearly complete cDNA codes for a 22 amino acid presequence and a 147 amino acid mature protein which shows 77 to 95% positional identity with the predicted sequences of human, bovine, and rat subunits. Screening of a mouse genomic $\lambda$EMBL3 library using the mouse cDNA probe yielded three overlapping clones. Restriction mapping and sequencing of the clones show that the mouse COXIV mRNA sequences are contained in five exons spanning a 7 kilobase region of the mouse genome. Southern blot analysis of genomic DNA indicates the presence of a single gene for mouse COXIV. Analysis of mouse RNA by Northern hybridization showed a single class of COXIV mRNA of approximately 0.68 kilobases in size. S1 mapping of the liver COXIV mRNA revealed multiple mRNA start sites clustered at two loci seperated by 20 nucleotides. Activity of the COXIV promoter is shown to depend upon upstream Spl binding sequences and two tandemly repeated 21 bp sequence elements, each mapping to sites of mRNA initiation. Each initiation region repeat contains a binding site for an ets-related transcription factor which demonstrates specificity for the characteristic GGAA ets sequence motif and reactivity with an ETS domain directed monoclonal pan ets antibody. The ets-related protein is shown to be identical or closely related to the GA-binding protein (GABP) by comparison of DNA-protein complex electrophoretic mobilities and immunological reactivities of the COS nuclear factor and of purified, recombinant expressed GABP $\alpha$ and $\beta$ subunits. Spl and the GABP-related factors are shown to bind to another COX subunit gene, mouse COXVb. The similar promoter features of these genes suggests a possible means of coordinate regulation amongst such respiratory proteins.

Subject Area

Biochemistry|Molecular biology

Recommended Citation

Carter, Robert Stuart, "Characterization of transcriptional control elements of the murine cytochrome c oxidase subunit IV gene" (1992). Dissertations available from ProQuest. AAI9235119.