Tag Content
UniProt Accession
Theoretical PI
Molecular Weight
10521 Da  
Genbank Nucleotide ID
Genbank Protein ID
Gene Name
Gene Synonyms/Alias
Protein Name
Cytochrome c oxidase subunit 6B2 
Protein Synonyms/Alias
Cytochrome c oxidase subunit VIb isoform 2;COX VIb-2 Cytochrome c oxidase subunit VIb, testis-specific isoform; 
Mus musculus (Mouse) 
NCBI Taxonomy ID
Chromosome Location
View in Ensembl genome browser  
Function in Stage
Function in Cell Type
Probability (GAS) of Function in Spermatogenesis
The probability was calculated by GAS algorithm, ranging from 0 to 1. The closer it is to 1, the more possibly it functions in spermatogenesis.
Temporarily unavailable 
Abstract of related literatures
1. Sperm motility is highly dependent on aerobic energy metabolism, of which the apparent rate-limiting step of the mitochondrial respiratory chain is catalyzed by cytochrome c oxidase (COX). COX is the only electron transport chain complex to display isoforms, consistent with its suggested rate-limiting role. Isoforms were previously described for four of the 13 subunits. We now report the discovery that COX subunit VIb displays a testes-specific isoform in human, bull, rat, and mouse (COX VIb-2). Analysis of a variety of rat and mouse tissues, including ovaries, demonstrates exclusive expression of VIb-2 in testes, whereas VIb-1 transcripts are absent in rodent testes, even at early developmental stages. In contrast, both isoforms are transcribed in human testes. In situ hybridizations with human, rat, and mouse testes sections reveal VIb-2 transcripts in all testicular cell types. Within the seminiferous tubules, VIb-1 shows stronger signals in the periphery than in the lumen. Previously, cytochrome c was the only component of the mitochondrial respiratory chain known to express a testes-specific isoform in mammals. COX subunit VIb connects the two COX monomers into the physiological dimeric form, and is the only COX subunit that, like cytochrome c, is solely located in the inter-membrane space. Significant differences between the isoform sequences, in particular changes in charged amino acids, suggest interactions with cytochrome c and sperm-specific energy requirements. PMID: [12874793] 

2. This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development. PMID: [16141072] 

3. The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline. PMID: [15489334] 

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This protein is one of the nuclear-coded polypeptidechains of cytochrome c oxidase, the terminal oxidase inmitochondrial electron transport. This protein may be one of theheme-binding subunits of the oxidase (By similarity). 
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Subcellular Location
Mitochondrion (By similarity). 
Tissue Specificity
Testis specific. 
Gene Ontology
GO IDGO termEvidence
GO:0030061 C:mitochondrial crista ISA:MGI.
GO:0004129 F:cytochrome-c oxidase activity IEA:InterPro.
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IPR003213;    Cyt_c_oxidase_su6B.
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PF02297;    COX6B;    1.
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Created Date
Record Type
GAS predicted 
Sequence Annotation
CHAIN         1     88       Cytochrome c oxidase subunit 6B2.
DISULFID     32     67       By similarity.
DISULFID     42     56       By similarity.
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Nucleotide Sequence
Length: 551 bp   Go to nucleotide: FASTA
Protein Sequence
Length: 88 bp   Go to amino acid: FASTA
The verified Protein-Protein interaction information
Gene Symbol Ref Databases
Other Protein-Protein interaction resources
String database  
View Microarray data