Characterization of the Brassica campestris mitochondrial gene for subunit six of NADH dehydrogenase: nad6 is present in the mitochondrion of a wide range of flowering plants

Nugent, Jacqueline M.; Palmer, Jeffrey D.

doi:10.1007/bf00352014

Cited by 13 publications

(2 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Second, many genes determining proteins that function in mitochondria or plastids actually reside in the eukaryotic nuclear genome. These genes most often resemble eubacterial homologues and are thought to have been transferred to the nucleus from the symbiont genome, in most cases soon after the endosymbiosis was established (11), although isolated instances of organelle to nucleus transfer occurring more recently in evolution can still be documented for both mitochondria and plastids (12)(13)(14)(15).In nearly all widely accepted instances of such transfer, the product of the transferred gene still functions in the organelle in which it originally resided. We are aware of only one clear case in which an organelle gene seems to have replaced a nuclear homologue and assumed its cytosolic function.…”

mentioning

confidence: 99%

Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin

Keeling

Doolittle

1997

Proc. Natl. Acad. Sci. U.S.A.

108

View full text Add to dashboard Cite

We have cloned and sequenced genes for triosephosphate isomerase (TPI) from the gamma-proteobacterium Francisella tularensis, the green non-sulfur bacterium Chloroflexus aurantiacus, and the alpha-proteobacterium Rhizobium etli and used these in phylogenetic analysis with TPI sequences from other members of the Bacteria, Archaea, and Eukarya. These analyses show that eukaryotic TPI genes are most closely related to the homologue from the alphaproteobacterium and most distantly related to archaebacterial homologues. This relationship suggests that the TPI genes present in modern eukaryotic genomes were derived from an alpha-proteobacterial genome (possibly that of the protomitochondrial endosymbiont) after the divergence of Archaea and Eukarya. Among these eukaryotic genes are some from deeply branching, amitochondrial eukaryotes (namely Giardia), which further suggests that this event took place quite early in eukaryotic evolution.For at least two decades, we have known that the genomes of most (if not all) eukaryotes are chimeric; their nuclei and DNA-containing organelles have different evolutionary histories (1). The bulk of the nuclear genome appears to share common ancestry with modern Archaea (archaebacteria). Rooted phylogenetic trees of translation elongation factors and aminoacyl-tRNA synthetases show that Archaea is the sister group of Eukarya (2, 3). In support of this, the sequences of many other essential components of the transcription and translation apparatus also reveal a strong archaebacterialeukaryotic affinity (4-6). In many instances, transcription and translation which are found in both archaebacteria and eukaryotes are altogether absent from eubacteria (for review see ref. 7). Mitochondria, on the other hand, are the degenerate descendants of once free-living eubacteria that entered into an endosymbiotic association with a (presumably nucleated) host cell early in the evolution of eukaryotes. The genes retained in the mitochondrial genome show that this eubacterium was what we would now call an alpha-proteobacterium, a relative of modern genera such as Rhizobium, Agrobacterium, and Rickettsia (8). Similarly, plastid genes derive from the genome of a photosynthetic endosymbiont whose nearest modern relatives are cyanobacteria (9).This picture of eukaryotic genome chimerism is further complicated in two ways. First, some lineages thought to have diverged soon after the origin of eukaryotes (Diplomonads and perhaps Microsporidia) have, in fact, no mitochondria. These lineages, which Cavalier-Smith has called Archezoa (10), may have never acquired mitochondria, and would therefore represent the original condition of the host in that respect. Second, many genes determining proteins that function in mitochondria or plastids actually reside in the eukaryotic nuclear genome. These genes most often resemble eubacterial homologues and are thought to have been transferred to the nucleus from the symbiont genome, in most cases soon after the endosymbiosis was established (11), although isolate...

show abstract

mentioning

confidence: 99%

Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin

Keeling

Doolittle

1997

Proc. Natl. Acad. Sci. U.S.A.

108

View full text Add to dashboard Cite

show abstract

“…These derive from a 220-bp segment located between about 900 and 780 bp upstream of the rpl5 reading frame, which is almost identical to part of the nad6 gene region from Brassica campestris. This sequence also hybridizes to the nad6 coding region in the pea mtDNA (data not shown, Nugent and Palmer 1993).…”

Section: Resultsmentioning

confidence: 90%

Cotranscription of the rpl5-rps14-cob gene cluster in pea mitochondria

Hoffmann¹,

Dombrowski²,

Guha³

et al. 1999

Mol Gen Genet

View full text Add to dashboard Cite

In pea mitochondria the rpl5, rpsl4 and cob ORFs are clustered in a unique genomic environment and are cotranscribed into a 4.7-kb primary transcript and several other polycistronic RNAs with sizes between 4.0 and 2.3 kb. All of the larger RNAs terminate at a common 3' end, 52 nucleotides downstream of the cob gene. Transcription is initiated at a promoter about 1.3 kb upstream of the rpl5 start codon. The promoter sequence 5'-AATAAGAGA-3' corresponds to the highly conserved 5'-CRTAAGAGA-3' motif often found in promoters in dicot plants. Functional analysis in a homologous in vitro transcription system showed the pea rpl5 promoter to be active, despite the presence of an altered base in first position of the promoter motif. In Oenothera, in contrast to pea, transcription of the rpl5 gene is driven by a promoter motif that conforms perfectly to the consensus sequence. Double inverted repeats located in the 3' flanking regions of the rpsl4 and cob ORFs in pea were investigated with respect to their possible role in defining transcript termini and their potential function in controlling exo- and endonucleolytic processing or transcript stabilization.

show abstract

Mitochondrial genome organization

Wolstenholme¹,

Fauron²

1995

The Molecular Biology of Plant Mitochondria

View full text Add to dashboard Cite

Characterization of the Brassica campestris mitochondrial gene for subunit six of NADH dehydrogenase: nad6 is present in the mitochondrion of a wide range of flowering plants

Cited by 13 publications

References 53 publications

Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin

Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin

Cotranscription of the rpl5-rps14-cob gene cluster in pea mitochondria

Mitochondrial genome organization

Contact Info

Product

Resources

About