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Gene Review:

Tb927.8.5120 - cytochrome c

Trypanosoma brucei brucei TREU927

Fang, J. et al., Feagin, J.E. et al., Markos, A. et al., Horváth, A. et al., Jasmer, D.P. et al., et al.

Fang, Beattie, Allen, Ginger, Ferguson,

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Disease relevance of Tb927.8.5120

Neither spontaneous nor catalysed maturation of the single-cysteine Trypanosoma brucei cytochrome c occurred in Escherichia coli [1].

High impact information on Tb927.8.5120

We have found 14 transcripts that are derived from a maxicircle (mitochondrial DNA) region that contains sequences homologous to cytochrome c oxidase subunits I and II, unassigned reading frame 1 from mitochondrial DNA of other organisms, and two other open reading frames [2].
We examined the expression of a nucleus-encoded mitochondrial protein, cytochrome c, during the life cycle of Trypanosoma brucei [3].
Transcription of a maxicircle segment from Trypanosoma brucei 164 that contains nucleotide (nt) sequences corresponding to cytochrome c oxidase subunit I (COI) and unassigned reading frames (URFs) 4 and 5 of other mitochondrial systems was investigated [4].
Cytochrome c reductase purified from the trypanosomatid Crithidia fasciculata retained antimycin A sensitivity and catalyzed the reduction of horse heart ferricytochrome c in the presence of reduced coenzyme Q10 [5].
The growth rates and oxygen consumption of clonal cell lines of knock-downs for apocytochrome c1 (apoc1) and the Rieske Fe-S protein (Rieske) of complex III, and cytochrome c oxidase subunit 6 (cox6) of complex IV were markedly decreased after RNAi induction [6].

Biological context of Tb927.8.5120

The reading frame coding for cytochrome c oxidase subunit II is discontinuous: the C-terminal portion of about 40 aminoacids, is present in the DNA-sequence in a -1 reading frame with respect to the N-terminal moiety [7].
The nucleotide sequence and its predicted translated sequence have homology to cytochrome c oxidase subunits I and II (CO I and II) and mammalian unidentified reading frame 1 (URF 1) [8].

Anatomical context of Tb927.8.5120

Experiments carried out with isolated mitochondrial membranes showed that, although the electron transfer from succinate to cytochrome c was inhibitable by antimycin, NADH-cytochrome c reductase was antimycin-insensitive [9].

Associations of Tb927.8.5120 with chemical compounds

The mitochondrial electron transfer chain present in the procyclic form of the African trypanosome Trypanosoma brucei contains both cytochrome c oxidase and an alternative oxidase (TAO) as terminal oxidases that reduce oxygen to water [10].
Antimycin A, a specific inhibitor of the cytochrome bc1 complex (ubiquinol:cytochrome c oxidoreductase), blocked almost completely cytochrome c reductase activity with either proline or succinate as electron donor, but had no inhibitory effect on NADH:ubiquinone oxidoreductase activity [11].
Other electron acceptors (i.e. oxygen or cytochrome c) appear to accept electrons in the absence of fumarate (KM for cytochrome c = 50 microM) [12].
Activities of procyclic-stage enzyme markers malate dehydrogenase, threonine dehydrogenase, succinate: cytochrome c reductase, and NADH: cytochrome c reductase rose within 48 h of differentiation to values which were close to those found in established procyclic forms [13].

Analytical, diagnostic and therapeutic context of Tb927.8.5120

Western blots, however, confirm that steady-state levels of cytochrome c are severely depressed in bloodstream forms [14].
RNase T1 protection studies and Northern blot analyses demonstrated that bloodstream and procyclic form cells constitutively expressed the genes for two nuclear encoded cytochrome c reductase subunits, cytochrome c1 and subunit 4 [15].

References

Maturation of the unusual single-cysteine (XXXCH) mitochondrial c-type cytochromes found in trypanosomatids must occur through a novel biogenesis pathway. Allen, J.W., Ginger, M.L., Ferguson, S.J. Biochem. J. (2004) [Pubmed]
Differential expression of mitochondrial genes between life cycle stages of Trypanosoma brucei. Feagin, J.E., Stuart, K. Proc. Natl. Acad. Sci. U.S.A. (1985) [Pubmed]
Posttranscriptional regulation of cytochrome c expression during the developmental cycle of Trypanosoma brucei. Torri, A.F., Hajduk, S.L. Mol. Cell. Biol. (1988) [Pubmed]
Diverse patterns of expression of the cytochrome c oxidase subunit I gene and unassigned reading frames 4 and 5 during the life cycle of Trypanosoma brucei. Jasmer, D.P., Feagin, J.E., Stuart, K. Mol. Cell. Biol. (1985) [Pubmed]
Cytochrome c reductase purified from Crithidia fasciculata contains an atypical cytochrome c1. Priest, J.W., Hajduk, S.L. J. Biol. Chem. (1992) [Pubmed]
Downregulation of the nuclear-encoded subunits of the complexes III and IV disrupts their respective complexes but not complex I in procyclic Trypanosoma brucei. Horváth, A., Horáková, E., Dunajcíková, P., Verner, Z., Pravdová, E., Slapetová, I., Cuninková, L., Lukes, J. Mol. Microbiol. (2005) [Pubmed]
The sequence of the gene for cytochrome c oxidase subunit I, a frameshift containing gene for cytochrome c oxidase subunit II and seven unassigned reading frames in Trypanosoma brucei mitochrondrial maxi-circle DNA. Hensgens, L.A., Brakenhoff, J., De Vries, B.F., Sloof, P., Tromp, M.C., Van Boom, J.H., Benne, R. Nucleic Acids Res. (1984) [Pubmed]
Identification of mitochondrial genes in Trypanosoma brucei and homology to cytochrome c oxidase II in two different reading frames. Payne, M., Rothwell, V., Jasmer, D.P., Feagin, J.E., Stuart, K. Mol. Biochem. Parasitol. (1985) [Pubmed]
The role of succinate in the respiratory chain of Trypanosoma brucei procyclic trypomastigotes. Turrens, J.F. Biochem. J. (1989) [Pubmed]
Alternative oxidase present in procyclic Trypanosoma brucei may act to lower the mitochondrial production of superoxide. Fang, J., Beattie, D.S. Arch. Biochem. Biophys. (2003) [Pubmed]
Isolation and characterization of complex I, rotenone-sensitive NADH: ubiquinone oxidoreductase, from the procyclic forms of Trypanosoma brucei. Fang, J., Wang, Y., Beattie, D.S. Eur. J. Biochem. (2001) [Pubmed]
A soluble fumarate reductase in Trypanosoma brucei procyclic trypomastigotes. Mracek, J., Snyder, S.J., Chavez, U.B., Turrens, J.F. J. Protozool. (1991) [Pubmed]
Metabolic differentiation of bloodstream forms of Trypanosoma brucei brucei into procyclic forms. Effect of hydroxyurea, arabinosyl adenine, and serum omission. Markos, A., Blahůsková, A., Kalous, M., Bysková, E., Byska, K., Nohýnková, E. Folia Parasitol. (1989) [Pubmed]
Protein stability regulates the expression of cytochrome c during the developmental cycle of Trypanosoma brucei. Torri, A.F., Bertrand, K.I., Hajduk, S.L. Mol. Biochem. Parasitol. (1993) [Pubmed]
Developmental regulation of Trypanosoma brucei cytochrome c reductase during bloodstream to procyclic differentiation. Priest, J.W., Hajduk, S.L. Mol. Biochem. Parasitol. (1994) [Pubmed]

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