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  • 1
    Digitale Medien
    Digitale Medien
    The evolutionary origin of red algae as deduced from the nuclear genes encoding cytosolic and chloroplast glyceraldehyde-3-phosphate dehydrogenases from Chondrus crispus (1994)
    Springer
    Journal of molecular evolution 38 (1994), S. 319-327 
    Details
    ISSN: 1432-1432
    Schlagwort(e): Molecular phylogeny of plastids and mitochondria ; Endosymbiotic origin ; Monophylesis ; Cyanobacteria ; Purple bacteria ; Transit peptide ; Neighbor joining method ; Bootstrapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Algae are a heterogeneous group of photosynthetic eukaryotes traditionally separated into three major subdivisions: rhodophytes, chlorophytes, and chromophytes. The evolutionary origin of rhodophytes or red algae and their links to other photosynthetic and nonphotosynthetic eukaryotes have been a matter of much controversy and speculation. Here we present the first cDNAs of nuclear protein genes from red algae: Those encoding cytosolic and chloroplast glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from Chondrus crispus. A phylogenetic analysis including GAPDH gene sequences from a number of eukaryotic taxa, cyanobacteria, and purple bacteria suggests that chloroplasts and rhodoplasts together form a monophyletic group of cyanobacterial descent and that rhodophytes separated from chlorophytes at about the same time as animals and fungi. The composite GAPDH tree further demonstrates that chloroplast and cytosolic GAPDH genes are closely related to their homologs in cyanobacteria and purple bacteria, respectively, the presumptive ancestors of chloroplasts and mitochondria, thereby firmly establishing the endosymbiotic origin of these nuclear genes and their fixation in eukaryotic cells before the rhodophyte/chlorophyte separation. The present data are in conflict with phylogenetic inferences based on plastid-encoded rbcL sequences supporting a polyphyletic origin of rhodoplasts and chloroplasts. Comparison of rbcL to GAPDH phylogenies suggests that rbcL trees may be misleading because they are composed of branches representing ancient duplicated (paralogous) genes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00163149
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  • 2
    Digitale Medien
    Digitale Medien
    Evolutionary Origin of Cryptomonad Microalgae: Two Novel Chloroplast/Cytosol-Specific GAPDH Genes as Potential Markers of Ancestral Endosymbiont and Host Cell Components (1997)
    Springer
    Journal of molecular evolution 44 (1997), S. S028 
    Details
    ISSN: 1432-1432
    Schlagwort(e): Key words:Pyrenomonas salina, Guillardia theta— Glyceraldehyde-3-phosphate dehydrogenase — Endosymbiotic gene transfer — Signal peptide — Enzyme engineering — Cell evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract. Cryptomonads are complex microalgae which share characteristics of chromophytes (chlorophyll c, extra pair of membranes surrounding the plastids) and rhodophytes (phycobiliproteins). Unlike chromophytes, however, they contain a small nucleus-like organelle, the nucleomorph, in the periplastidial space between the inner and outer plastid membrane pairs. These cellular characteristics led to the suggestion that cryptomonads may have originated via a eukaryote–eukaryote endosymbiosis between a phagotrophic host cell and a unicellular red alga, a hypothesis supported by rRNA phylogenies. Here we characterized cDNAs of the nuclear genes encoding chloroplast and cytosolic glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from the two cryptomonads Pyrenomonas salina and Guillardia theta. Our results suggest that in cryptomonads the classic Calvin cycle GAPDH enzyme of cyanobacterial origin, GapAB, is absent and functionally replaced by a photosynthetic GapC enzyme of proteobacterial descent, GapC1. The derived GapC1 precursor contains a typical signal/transit peptide of complex structure and sequence signatures diagnostic for dual cosubstrate specificity with NADP and NAD. In addition to this novel GapC1 gene a cytosol-specific GapC2 gene of glycolytic function has been found in both cryptomonads showing conspicuous sequence similarities to animal GAPDH. The present findings support the hypothesis that the host cell component of cryptomonads may be derived from a phototrophic rather than a organotrophic cell which lost its primary plastid after receiving a secondary one. Hence, cellular compartments of endosymbiotic origin may have been lost or replaced several times in eukaryote cell evolution, while the corresponding endosymbiotic genes (e.g., GapC1) were retained, thereby increasing the chimeric potential of the nuclear genome.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00000050
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  • 3
    Digitale Medien
    Digitale Medien
    Endosymbiotic origin and codon bias of the nuclear gene for chloroplast glyceraldehyde-3-phosphate dehydrogenase from maize (1987)
    Springer
    Journal of molecular evolution 26 (1987), S. 320-328 
    Details
    ISSN: 1432-1432
    Schlagwort(e): cDNAs ; GAPDH evolutionary tree ; Horizontal gene transfer ; Coding strategies ; Monocotyledons ; Dicotyledons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nuclei of plant cells harbor genes for two types of glyceraldehyde-3-phosphate dehydrogenases (GAPDH) displaying a sequence divergence corresponding to the prokaryote/eukaryote separation. This strongly supports the endosymbiotic theory of chloroplast evolution and in particular the gene transfer hypothesis suggesting that the gene for the chloroplast enzyme, initially located in the genome of the endosymbiotic chloroplast progenitor, was transferred during the course of evolution into the nuclear genome of the endosymbiotic host. Codon usage in the gene for chloroplast GAPDH of maize is radically different from that employed by present-day chloroplasts and from that of the cytosolic (glycolytic) enzyme from the same cell. This reveals the presence of subcellular selective pressures which appear to be involved in the optimization of gene expression in the economically important graminaceous monocots.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02101150
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  • 4
    Digitale Medien
    Digitale Medien
    Origin of introns–early or late? (1994)
    [s.l.] : Nature Publishing Group
    Nature 369 (1994), S. 527-528 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] CERFF EI AL. REPLY - Logsdon/Palmer and Stoltzfus suggest that the five identical intron positions across chloroplast and cytosolic GAPDH genes (GapAlB and GapC, respectively) are best explained by parallel insertions at common target sites rather than by common ancestry. But if relatively late ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/369527a0
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  • 5
    Digitale Medien
    Digitale Medien
    Five identical intron positions in ancient duplicated genes of eubacterial origin (1994)
    [s.l.] : Nature Publishing Group
    Nature 367 (1994), S. 387-389 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Two introns strictly conserved in nuclear genes encoding chloroplast and cytosolic glyceraldehyde-3-phosphate dehydrogenases (GAPDH; Gap A/Gap B and GapC, respectively) have been generally regarded as strong evidence in favour of the 'introns early' hypothesis10, although the identity of intron ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/367387a0
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  • 6
    Digitale Medien
    Digitale Medien
    Structural features and phylogeny of the actin gene of Chondrus crispus (Gigartinales, Rhodophyta) (1995)
    Springer
    Current genetics 28 (1995), S. 164-172 
    Details
    ISSN: 1432-0983
    Schlagwort(e): Chondrus crispus ; Actin ; Promoter region Intron
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have characterized the cDNA and genomic sequences that encode actin from the multicellular red alga Chondrus crispus. Southern-blot analysis indicates that the C. crispus actin gene (ChAc) is present as a single copy. Northern analysis shows that, like the GapA gene, the actin gene is well expressed in gametophytes but weakly in protoplasts. Compared to actin genes of animals, fungi, green plants and oomycetes, that of C. crispus displays a higher evolutionary rate and does not show any of the amino-acid signatures characteristic of the other lineages. As previously described for GapA, ChAc is interrupted by a single intron at the beginning of the coding region. The site of initiation of transcription was characterized by RNAse protection. The promoter region displays a CAAT box but lacks a canonical TATA motif. Other noticeable features, such as a high content of pyrimidines as well as a 14-nt motif found in both the 5′-untranslated region and the intron, were observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315783
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  • 7
    Digitale Medien
    Digitale Medien
    Transaldolase genes from the cyanobacteria Anabaena variabilis and Synechocystis sp. PCC 6803: comparison with other eubacterial and eukaryotic homologues (1996)
    Springer
    Plant molecular biology 30 (1996), S. 213-218 
    Details
    ISSN: 1573-5028
    Schlagwort(e): carbohydrate metabolism ; gene phylogeny ; oxidative pentose-phosphate pathway ; transaldolase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have sequenced and analysed the transaldolase (tal) genes from two cyanobacteria, Anabaena variabilis (ATCC 29413) and Synechocystis sp. PCC 6803, which are filamentous heterocyst-forming and unicellular organisms, respectively. The deduced amino acid sequences of the two cyanobacterial tal genes are 78% identical and are highly homologous to both eubacterial and eukaryotic transaldolases (Escherichia coli, two yeasts, and man) with values ranging from 54 to 60% amino acid identity. In contrast, the transaldolase homologous sequences from the cyanobacterium Nostoc sp. ATCC 29133, from Mycobacterium leprae, and the partial sequence from the higher plant Arabidopsis thaliana have a much lower degree of homology with each other and relative to the sequences mentioned above. These data indicate three different types of transaldolases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00017817
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  • 8
    Digitale Medien
    Digitale Medien
    The marine red alga Chondrus crispus has a highly divergent β-tubulin gene with a characteristic 5′ intron: functional and evolutionary implications (1995)
    Springer
    Plant molecular biology 28 (1995), S. 313-325 
    Details
    ISSN: 1573-5028
    Schlagwort(e): red algae ; Chondrus crispus ; β-tubulin ; gene families ; isoform diversity ; intron loss
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We characterized a nuclear gene and its corresponding cDNA encoding β-tubulin (gene TubB1) of the marine red alga Chondrus crispus. The deduced TubB1 protein is the most divergent β-tubulin so far reported with only 64 to 69% amino acid identity relative to other β-tubulins from higher and lower eukaryotes. Our analysis reveals that TubB1 has an accelerated evolutionary rate probably due to a release of functional constraints in connexion with a specialization of microtubular structures in rhodophytes. It further indicates that isoform diversity and functional differentiation of tubulins in eukaryotic cells may be controlled by independent selective constraints. TubB1 has a short spliceosomal intron at its 5′ end which seems to be a characteristic feature of nuclear protein-coding genes from rhodophytes. The splice junctions of the four known rhodophyte introns comply well with the corresponding consensus sequences of higher plants in agreement with previous suggestions from phylogenetic inference that red algae and green plants may be sister groups. The paucity and asymmetrical location of introns in rhodophyte genes can be explained by differential intron loss due to conversion of genes by homologous recombination with cDNAs corresponding to reverse transcribed mRNAs or partially spliced pre-mRNAs, respectively. The identification of an intron containing TubB1 cDNA in C. crispus confirms that pre-mRNAs can escape both splicing and degradation in the nucleus prior to transport into the cytoplasm. Differential Southern hybridizations under non-stringent conditions with homologous and heterologous probes suggest that C. crispus contains a second degenerate β-tubulin gene (or pseudogene?) which, however, is only distantly related to TubB1 as it is to the more conserved homologues of other organisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020250
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  • 9
    Digitale Medien
    Digitale Medien
    The β-tubulin gene family of pea: Primary structures, genomic organization and intron-dependent evolution of genes (1992)
    Springer
    Plant molecular biology 18 (1992), S. 639-651 
    Details
    ISSN: 1573-5028
    Schlagwort(e): dispensable proteins ; evolutionary rates ; exon theory of genes ; homologous recombination ; intron shift ; multigene family
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract One gene and two cDNAs encoding three different β-tubulins (TUB1, TUB2, TUB3) of pea have been cloned and sequenced. The derived amino acid sequences show between 92% and 96% identity relative to one another and to most other β-tubulins of higher plants and green algae. Two notable extremes are the high similarity of 98% between pea TUB3 and maize β-tubulin 2 and the relatively low similarity (90%) of the hypocotyl-specific β-tubulin 1 of soybean to the pea sequences. These similarities do not reflect the molecular phylogeny but rather differences in evolutionary rate of β-tubulins which are differentially regulated during plant development. Genomic Southern blots reveal a β-tubulin gene family in pea with at least four separate members including two TUB1 genes, one TUB2 gene and one TUB3 gene. This contradicts an earlier report by Rahaet al. (Plant Mol Biol 9: 565–571, 1987) suggesting a tandem repeat organization of tubulin genes in pea. The pea TUB1 gene has two introns in identical positions compared to the β-tubulin genes fromArabidopsis and soybean. In an attempt to reconstruct the universal ancestor of all present-day tubulin genes the intron positions in 38 different α- and β-tubulin genes from plants, animals, fungi and protozoa were compared. This comparison shows that the primordial gene probably had many introns (more than 20) separating ‘protoexons’ of 15 to 20 codons in agreement with the ‘exon theory of genes’. It also supports the view that, during the course of evolutions introns have shifted and were deleted preferentially in the 3′ part of the genes. Similar observations have been made previously for other genes. They can be interpreted in terms of a homologous recombination of genes with their modified (incorrectly spliced) and reverse-transcribed pre-mRNAs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020007
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  • 10
    Digitale Medien
    Digitale Medien
    Molecular characterization of a novel, nuclear-encoded, NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase in plastids of the gymnosperm Pinus sylvestris L. (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1155-1166 
    Details
    ISSN: 1573-5028
    Schlagwort(e): sugar phosphate metabolism ; chloroplast ; cDNA cloning ; in vitro import ; endosymbiotic gene transfer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Angiosperms and algae possess two distinct glyceraldehyde-3-phosphate dehydrogenase (GAPDH) enzymes, an NAD+-dependent tetramer involved in cytosolic glycolysis and an NADP+-dependent enzyme of the Calvin cycle in chloroplasts. We have found that the gymnosperm Pinus sylvestris possesses, in addition to these, a nuclear-encoded, plastid-specific, NAD+-dependent GAPDH, designated GapCp, which has not previously been described from any plant. Several independent full-size cDNAs for this enzyme were isolated which encode a functional transit peptide and mature subunit very similar to that of cytosolic GAPDH of angiosperms and algae. A molecular phylogeny reveals that chloroplast GapCp and cytosolic GapC arose through gene duplication early in chlorophyte evolution. The GapCp gene is expressed as highly as that for GapC in light-grown pine seedlings. These findings suggest that aspects of compartmentalized sugar phosphate metabolism may differ in angiosperms and gymnosperms and furthermore underscore the contributions of endosymbiotic gene transfer and gene duplication to the nuclear complement of genes for enzymes of plant primary metabolism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00040696
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