THE <i>atp</i>A GENE CLUSTER OF <i>GUILLARDIA THETA</i> (CRYPTOPHYTA): A PIECE IN THE PUZZLE OF CHLOROPLAST GENOME EVOLUTION

Leitsch, Carola E. W.; Kowallik, Klaus V.; Douglas, Susan E.

doi:10.1046/j.1529-8817.1999.3510128.x

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…In chlorarachniophytes and cryptomonads, which contain periplastid ERs (Corliss 1994) but do not belong to the stramenopiles in rRNA trees (Cavalier-Smith 1993; Van de Peer and De Wachter 1997), the periplastid space harbors remnants of an engulfed cell's nucleus, the nucleomorph (Gilson, Maier, and McFadden 1997), indicating that these algae originated via eukaryote-eukaryote endosymbioses between a phagotrophic host cell and an unicellular microalga (Gibbs 1981;Sitte 1993;McFadden and Gilson 1995;Douglas 1998). Although diatoms, like most photosynthetic heterokontflagellated protists, have not preserved a nucleomorph, molecular data indicate that their four membrane-bounded plastids descend from a eukaryotic red alga Leitsch, Kowallik, and Douglas 1999). To see if traces of this complex symbiotic history might be preserved in the compartmentation of their energy metabolism, we investigated the compartment-specific isoforms of GAPDH and TPI in diatoms.…”

Section: Discussionmentioning

confidence: 99%

“…The ability of individual genes to accurately reflect deep phylogenetic relationships among eukaryotes is a debated issue (Embley and Hirt 1998;Philippe and Laurent 1998). TPI-GAPDH and similar gene clusters (Leitsch, Kowallik, and Douglas 1999) can help to untangle the conundrum of protist evolution.…”

Section: Diatom Mitochondria: a Missing Metabolic Link Of Organelle Ementioning

confidence: 99%

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Compartment-Specific Isoforms of TPI and GAPDH are Imported into Diatom Mitochondria as a Fusion Protein: Evidence in Favor of a Mitochondrial Origin of the Eukaryotic Glycolytic Pathway

Liaud¹,

Lichtl²,

Apt³

et al. 2000

Molecular Biology and Evolution

120

103

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Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and triosephosphate isomerase (TPI) are essential to glycolysis, the major route of carbohydrate breakdown in eukaryotes. In animals and other heterotrophic eukaryotes, both enzymes are localized in the cytosol; in photosynthetic eukaryotes, GAPDH and TPI exist as isoenzymes that function in the glycolytic pathway of the cytosol and in the Calvin cycle of chloroplasts. Here, we show that diatoms--photosynthetic protists that acquired their plastids through secondary symbiotic engulfment of a eukaryotic rhodophyte--possess an additional isoenzyme each of both GAPDH and TPI. Surprisingly, these new forms are expressed as an TPI-GAPDH fusion protein which is imported into mitochondria prior to its assembly into a tetrameric bifunctional enzyme complex. Homologs of this translational fusion are shown to be conserved and expressed also in nonphotosynthetic, heterokont-flagellated oomycetes. Phylogenetic analyses show that mitochondrial GAPDH and its N-terminal TPI fusion branch deeply within their respective eukaryotic protein phylogenies, suggesting that diatom mitochondria may have retained an ancestral state of glycolytic compartmentation that existed at the onset of mitochondrial symbiosis. These findings strongly support the view that nuclear genes for enzymes of glycolysis in eukaryotes were acquired from mitochondrial genomes and provide new insights into the evolutionary history (host-symbiont relationships) of diatoms and other heterokont-flagellated protists.

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Section: Discussionmentioning

confidence: 99%

Section: Diatom Mitochondria: a Missing Metabolic Link Of Organelle Ementioning

confidence: 99%

Compartment-Specific Isoforms of TPI and GAPDH are Imported into Diatom Mitochondria as a Fusion Protein: Evidence in Favor of a Mitochondrial Origin of the Eukaryotic Glycolytic Pathway

Liaud¹,

Lichtl²,

Apt³

et al. 2000

Molecular Biology and Evolution

120

103

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“…Köhler et al (1997) concluded that there was no a priori reason to believe that it was related to the plastids of dinoflagellates and indicated that the plastid may be derived from the green lineage. A different view has been presented on the basis of gene content and arrangement in the plastid genome, which are more consistent with a nongreen origin of the apicomplexan plastid (McFadden and Waller 1997;Blanchard and Hicks 1998;Leitsch et al 1999). These analyses are complicated by the difficulty of determining homology in the highly divergent Plasmodium falciparum plastid, but they are at least as compelling as single-gene analyses.…”

Section: Plastids In the Alveolata: A Microcosm Of Plastid Evolutionmentioning

confidence: 99%

Tracing the Thread of Plastid Diversity through the Tapestry of Life

Delwiche

1999

The American Naturalist

359

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Plastids (chloroplasts) are endosymbiotic organelles derived from previously free-living cyanobacteria. They are dependent on their host cell to the degree that the majority of the proteins expressed in the plastid are encoded in the nuclear genome of the host cell, and it is this genetic dependency that distinguishes organelles from obligate endosymbionts. Reduction in the size of the plastid genome has occurred via gene loss, substitution of nuclear genes, and gene transfer. The plastids of Chlorophyta and plants, Rhodophyta, and Glaucocystophyta are primary plastids (i.e., derived directly from a cyanobacterium). These three lineages may or may not be descended from a single endosymbiotic event. All other lineages of plastids have acquired their plastids by secondary (or tertiary) endosymbiosis, in which a eukaryote already equipped with plastids is preyed upon by a second eukaryote. Considerable gene transfer has occurred among genomes and, at times, between organisms. The eukaryotic crown group Alveolata has a particularly complex history of plastid acquisition.

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“…Phylogenetic analyses of nucleus‐encoded genes for ribosomal RNA [11], tubulins [12], glycolytic glyceraldehyde dehydrogenase [13], the ER‐specific protein calreticulin [14] and mitochondrial Hsp60 [15], as well as the mitochondrion‐encoded coxI gene [15,16] strongly support this relationship. The endosymbiont that has developed into today's euglenid chloroplast was shown in cytological studies [1] and the comparative analysis of chloroplast genomes [17–20] to be derived from a eukaryotic green alga.…”

mentioning

confidence: 99%

Chloroplast phosphoglycerate kinase from Euglena gracilis

Nowitzki

Gelius-Dietrich

Schwieger

et al. 2004

European Journal of Biochemistry

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Two chloroplast phosphoglycerate kinase isoforms from the photosynthetic flagellate Euglena gracilis were purified to homogeneity, partially sequenced, and subsequently cDNAs encoding phosphoglycerate kinase isoenzymes from both the chloroplast and cytosol of E. gracilis were cloned and sequenced. Chloroplast phosphoglycerate kinase, a monomeric enzyme, was encoded as a polyprotein precursor of at least four mature subunits that were separated by conserved tetrapeptides. In a Neighbor-Net analysis of sequence similarity with homologues from numerous prokaryotes and eukaryotes, cytosolic phosphoglycerate kinase of E. gracilis showed the highest similarity to cytosolic and glycosomal homologues from the Kinetoplastida. The chloroplast isoenzyme of E. gracilis did not show a close relationship to sequences from other photosynthetic organisms but was most closely related to cytosolic homologues from animals and fungi. [17][18][19][20] to be derived from a eukaryotic green alga.Essential to the compartmentation of sugar phosphate metabolism between chloroplast and cytosol in Euglena are glycolytic Calvin cycle isoenzyme pairs [21]. Glycolytic 3-phosphoglycerate kinase (PGK, EC 2.7.2.3) catalyses the ADP-dependent dephosphorylation of 1,3-bisphosphoglycerate to 3-bisphosophoglycerate. A chloroplast isoform in photosynthetic eukaryotes catalyses the reverse reaction as part of the Calvin cycle. In the Kinetoplastida, the closest relatives of Euglena gracilis, two glycolytic isoforms of PGK have been detected. One is located in the cytosol and the other in the glycosomes, specialized peroxisomes harbouring the first seven steps of glycolysis. Both isoforms are derived from a gene duplication and in phylogenetic analysis were shown to be monophyletic with, but highly divergent from, cytosolic orthologs in protozoa, fungi and animals [22]. In plants the cytosolic PGK was replaced by a copy of the chloroplast isoform, acquired from the cyanobacterial endosymbiont that gave rise to the plastids [23].Here we report the purification and cloning of the chloroplast PGK (cpPGK) from Euglena gracilis which is translated as a polyprotein precursor, cloning of the cytosolic PGK isoenzyme (cPGK), and the histories of both PGK isoforms in the context of endosymbiotic gene acquisitions. Materials and methods Strain and culture conditionsEuglena gracilis strain SAG 1224-5/25 was grown in 5 L of Euglena medium with minerals [24] under continuous light and a constant flow of 2 LAEmin )1 air with 2% (v/v) CO 2 . Cells were harvested 5 days after inoculation. PGK purification from whole cells and chloroplastsAll steps were performed at 4°C unless stated otherwise. Euglena cells (200 g) were homogenized in buffer 1 (10 mM Tris/HCl pH 7.5, 1 mM dithiothreitol) using a French-Press at 8000 p.s.i. and centrifuged for 30 min at 27 500 g. The 30-80% ammonium sulfate fraction of the supernatant was

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THE atpA GENE CLUSTER OF GUILLARDIA THETA (CRYPTOPHYTA): A PIECE IN THE PUZZLE OF CHLOROPLAST GENOME EVOLUTION

Cited by 7 publications

References 28 publications

Compartment-Specific Isoforms of TPI and GAPDH are Imported into Diatom Mitochondria as a Fusion Protein: Evidence in Favor of a Mitochondrial Origin of the Eukaryotic Glycolytic Pathway

Compartment-Specific Isoforms of TPI and GAPDH are Imported into Diatom Mitochondria as a Fusion Protein: Evidence in Favor of a Mitochondrial Origin of the Eukaryotic Glycolytic Pathway

Tracing the Thread of Plastid Diversity through the Tapestry of Life

Chloroplast phosphoglycerate kinase from Euglena gracilis

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