Transfer RNA genes of Euglena gracilis chloroplast DNA

Hallick, Richard B.; Hollingsworth, Margaret J.; Nickoloff, Jac A.

doi:10.1007/bf00016064

Cited by 60 publications

(55 citation statements)

References 24 publications

(13 reference statements)

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“…The cox1 gene of the button mushroom Agaricus bisporus has 19 introns, making it the largest (29.9 kb) and most intron-rich organelle gene from all eukaryotes (66). The types and arrangements of introns within organelle DNAs can be quite bizarre: the Euglena gracilis plastid genome contains 15 twintrons (introns within introns), which must be removed sequentially for accurate splicing (65); in the S. moellendorffii mtDNA, nad4L is located within an intron of nad1 (42).…”

Section: A Multiplicity Of Mitochondrial and Plastid Genome Architectmentioning

confidence: 99%

Mitochondrial and plastid genome architecture: Reoccurring themes, but significant differences at the extremes

Smith

Keeling

2015

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

343

344

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Mitochondrial and plastid genomes show a wide array of architectures, varying immensely in size, structure, and content. Some organelle DNAs have even developed elaborate eccentricities, such as scrambled coding regions, nonstandard genetic codes, and convoluted modes of posttranscriptional modification and editing. Here, we compare and contrast the breadth of genomic complexity between mitochondrial and plastid chromosomes. Both organelle genomes have independently evolved many of the same features and taken on similar genomic embellishments, often within the same species or lineage. This trend is most likely because the nuclear-encoded proteins mediating these processes eventually leak from one organelle into the other, leading to a high likelihood of processes appearing in both compartments in parallel. However, the complexity and intensity of genomic embellishments are consistently more pronounced for mitochondria than for plastids, even when they are found in both compartments. We explore the evolutionary forces responsible for these patterns and argue that organelle DNA repair processes, mutation rates, and population genetic landscapes are all important factors leading to the observed convergence and divergence in organelle genome architecture.E ndosymbiosis can dramatically impact cellular and genomic architectures. Mitochondria and plastids exemplify this point. Each of these two types of energy-producing eukaryotic organelle independently arose from the endosymbiosis, retention, and integration of a free-living bacterium into a host cell more than 1.4 billion years ago. Mitochondria came first, evolving from an alphaproteobacterial endosymbiont in an ancestor of all known living eukaryotes, and still exist, in one form or another (1), in all its descendants (2). Plastids came later, via the "primary" endosymbiosis of a cyanobacterium by the eukaryotic ancestor of the Archaeplastida, and then spread laterally to disparate groups through eukaryote-eukaryote endosymbioses (3). Consequently, a significant proportion of the identified eukaryotic diversity has a plastid.With few exceptions (1, 4), mitochondria and plastids contain genomes-chromosomal relics of the bacterial endosymbionts from which they evolved (2, 5). Mitochondrial and plastid DNAs (mtDNAs and ptDNAs) have many traits in common, which is not surprising given their similar evolutionary histories. Both are highly reduced relative to the genomes of extant, free-living alphaproteobacteria and cyanobacteria (2, 5), and both have transferred most of their genes to the host nuclear genome and are therefore reliant on nuclear-encoded, organelle-targeted proteins for the preservation of crucial biochemical pathways and many repair-, replication-, and expression-related functions (6). Both also show a wide and perplexing assortment of genomic architectures (7,8), which has spurred various evolutionary explanations, ranging from ancient inheritance from the RNA world to selection for greater "evolvability" (9, 10).At first glance, genomic complexity w...

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Section: A Multiplicity Of Mitochondrial and Plastid Genome Architectmentioning

confidence: 99%

Mitochondrial and plastid genome architecture: Reoccurring themes, but significant differences at the extremes

Smith

Keeling

2015

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

343

344

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“…Once again, a corresponding gene is present on the plastid genome of the red alga Porphyra purpurea but not on the plastids of higher plants. The gene is also absent from the only other fully sequenced plastid genome presently available from a protist, that of Euglena gracilis (51). The malarial clpC gene is unusual in that only the second of the two ATP binding domains is conserved.…”

Section: Single-copy Region (Ir B Sector)mentioning

confidence: 99%

Extrachromosomal DNA in the Apicomplexa

Wilson¹,

Gardner²,

Rangachari³

et al. 1993

Toxoplasmosis

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“…The "green" side of the equation is relatively straightforward. Two algal groups, the euglenids and chlorarachniophytes, harbor chlorophyll a+b-pigmented plastids, which are surrounded by three and four membranes, respectively (41)(42)(43). The chlorarachniophytes are of particular interest in that the nucleus of the green algal endosymbiont persists in a miniaturized form called a "nucleomorph" (44,45).…”

Section: Evolving a Complex Algamentioning

confidence: 99%

Genomic perspectives on the birth and spread of plastids

Archibald

2015

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

125

113

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The endosymbiotic origin of plastids from cyanobacteria was a landmark event in the history of eukaryotic life. Subsequent to the evolution of primary plastids, photosynthesis spread from red and green algae to unrelated eukaryotes by secondary and tertiary endosymbiosis. Although the movement of cyanobacterial genes from endosymbiont to host is well studied, less is known about the migration of eukaryotic genes from one nucleus to the other in the context of serial endosymbiosis. Here I explore the magnitude and potential impact of nucleus-to-nucleus endosymbiotic gene transfer in the evolution of complex algae, and the extent to which such transfers compromise our ability to infer the deep structure of the eukaryotic tree of life. In addition to endosymbiotic gene transfer, horizontal gene transfer events occurring before, during, and after endosymbioses further confound our efforts to reconstruct the ancient mergers that forged multiple lines of photosynthetic microbial eukaryotes.

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Transfer RNA genes of Euglena gracilis chloroplast DNA

Cited by 60 publications

References 24 publications

Mitochondrial and plastid genome architecture: Reoccurring themes, but significant differences at the extremes

Mitochondrial and plastid genome architecture: Reoccurring themes, but significant differences at the extremes

Extrachromosomal DNA in the Apicomplexa

Genomic perspectives on the birth and spread of plastids

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