Alternative titles; symbols
HGNC Approved Gene Symbol: COX5B
Cytogenetic location: 2q11.2 Genomic coordinates (GRCh38): 2:97,646,062-97,648,383 (from NCBI)
Subunit Vb of mammalian cytochrome c oxidase (COX; EC 1.9.3.1) is encoded by a nuclear gene and assembled with the other 12 COX subunits encoded in both mitochondrial and nuclear DNA. COX, the terminal enzyme of the electron transport chain, transfers electrons from reduced cytochrome c to oxygen and, in the process, generates an electrochemical gradient across the mitochondrial inner membrane. The enzyme is composed of 13 polypeptide subunits, 3 of which are encoded in mitochondrial DNA and 10 in nuclear DNA. The nuclear-coded COX subunits can be divided into 2 groups: those with muscle-specific isoforms and those that are identical in all tissues, such as COX5B (summary by Lomax et al., 1991).
Lomax et al. (1991) reported the isolation and DNA sequence of the expressed gene for human COX subunit Vb and the chromosomal location of the expressed gene and 7 pseudogenes as determined by analysis of panels of somatic cell hybrids with cDNA, genomic, and intron probes.
Lomax et al. (1991) determined that the COX5B gene contains 5 exons and 4 introns. The 4 coding exons span a region of approximately 2.4 kb. The 5-prime end of the COX5B gene is GC-rich and contains many HpaII sites.
Using genomic Southern blot analysis of human DNA probed with the human COX Vb cDNA, Lomax et al. (1991) identified 8 restriction fragments containing COX Vb-related sequences that were mapped to different chromosomes with panels of human/Chinese somatic cell hybrids. Because only 1 of these fragments hybridized with a 210-bp probe from intron 4, Lomax et al. (1991) concluded that there is a single expressed gene in the human genome, which they mapped to 2cen-q13.
Lomax, M. I., Hsieh, C.-L., Darras, B. T., Francke, U. Structure of the human cytochrome c oxidase subunit Vb gene and chromosomal mapping of the coding gene and of seven pseudogenes. Genomics 10: 1-9, 1991. [PubMed: 1646156] [Full Text: https://doi.org/10.1016/0888-7543(91)90476-u]