Unusual Mitochondrial Genome Structures throughout the Euglenozoa

Roy, Joannie; Faktorová, Drahomíra; Lukeš, Julius; Burger, Gertraud

doi:10.1016/j.protis.2007.03.002

Cited by 51 publications

(42 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Most nucleoids in the mitochondria are spherical or ovoid and are, with a diameter of 70-130 nm, smaller than those in plastids (Hayashi-Isimaru et al 1993). Many attempts to analyze the mitochondrial genome of E. gracilis failed and led only to the detection of a single cox1-bearing fragment (Tessier et al 1997;Yasuhira and Simpson 1997), so mtDNA structure and size remained elusive (Roy et al 2007), until Spencer and Gray (2011) established the general architecture of E. gracilis mtDNA. They isolated mtDNA comprising a heterodisperse collection of short linear fragments of heterogeneous size (modal size 4 kbp) bearing terminal repeats and many small, likely nonfunctional protein and rRNA gene fragments and showed that the mitochondrial large and small subunit rRNA are each split into two pieces (Spencer and Gray 2011).…”

Section: The Mitochondrial Genomementioning

confidence: 99%

The Mitochondrion of Euglena gracilis

Zimorski

Rauch

Hellemond

et al. 2017

Advances in Experimental Medicine and Biology

View full text Add to dashboard Cite

In the presence of oxygen, Euglena gracilis mitochondria function much like mammalian mitochondria. Under anaerobiosis, E. gracilis mitochondria perform a malonyl-CoA independent synthesis of fatty acids leading to accumulation of wax esters, which serve as the sink for electrons stemming from glycolytic ATP synthesis and pyruvate oxidation. Some components (enzymes and cofactors) of Euglena's anaerobic energy metabolism are found among the anaerobic mitochondria of invertebrates, others are found among hydrogenosomes, the H-producing anaerobic mitochondria of protists.

show abstract

Section: The Mitochondrial Genomementioning

confidence: 99%

The Mitochondrion of Euglena gracilis

Zimorski

Rauch

Hellemond

et al. 2017

Advances in Experimental Medicine and Biology

View full text Add to dashboard Cite

show abstract

“…A recent study, using UMSBP affinity chromatography of Leishmania major cell lysate, followed by mass spectrometry of the UMSBP-bound proteins, as well as yeast two-hybrid analysis, revealed the specific interactions between UMSBP and TXNPx. 4 Finally, although not interpreted as a direct effect on the redox state of UMSBP but rather as the result of the depletion of reduced TXN, it has been recently found that overexpression of TbTXNPx resulted in an increase in UMSBP oligomerization and loss of kDNA (36).…”

Section: A Cell Cycle-dependent Control Of the Umsbp Redox Statementioning

confidence: 99%

Enzymatic Mechanism Controls Redox-mediated Protein-DNA Interactions at the Replication Origin of Kinetoplast DNA Minicircles

Sela¹,

Yaffe²,

Shlomai³

2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

Kinetoplast DNA (kDNA) is the mitochondrial DNA of trypanosomatids. Its major components are several thousand topologically interlocked DNA minicircles. Their replication origins are recognized by universal minicircle sequence-binding protein (UMSBP), a CCHC-type zinc finger protein, which has been implicated with minicircle replication initiation and kDNA segregation. Interactions of UMSBP with origin sequences in vitro have been found to be affected by the protein's redox state. Reduction of UMSBP activates its binding to the origin, whereas UMSBP oxidation impairs this activity. The role of redox in the regulation of UMSBP in vivo was studied here in synchronized cell cultures, monitoring both UMSBP origin binding activity and its redox state, throughout the trypanosomatid cell cycle. These studies indicated that UMSBP activity is regulated in vivo through the cell cycle dependent control of the protein's redox state. The hypothesis that UMSBP's redox state is controlled by an enzymatic mechanism, which mediates its direct reduction and oxidation, was challenged in a multienzyme reaction, reconstituted with pure enzymes of the trypanosomal major redox-regulating pathway. Coupling in vitro of this reaction with a UMSBP origin-binding reaction revealed the regulation of UMSBP activity through the opposing effects of tryparedoxin and tryparedoxin peroxidase. In the course of this reaction, tryparedoxin peroxidase directly oxidizes UMSBP, revealing a novel regulatory mechanism for the activation of an origin-binding protein, based on enzyme-mediated reversible modulation of the protein's redox state. This mode of regulation may represent a regulatory mechanism, functioning as an enzyme-mediated, redox-based biological switch.2 is a unique extrachromosomal DNA network, found in the single mitochondrion of trypanosomatids. It consists, in the species Crithidia fasciculata, of ϳ5,000 duplex DNA minicircles of 2.5 kbp and ϳ50 maxicircles of 37 kbp that are interlocked topologically to form a DNA network. Two short sequences, the dodecameric universal minicircle sequence (UMS), GGGGTTGGTGTA, and the hexameric sequence ACGCCC, which were located at the minicircle's replication origin and implicated with its replication initiation, were conserved in all trypanosomatid species studied (recently reviewed in Refs.

show abstract

“…The mitochondrial genomes of two other euglenids, Peranema trichophorum and Petalomonas cantuscygni have been examined using electron microscopy (Roy et al 2007). These results show that the P. trichophorum genome consists of many linear DNA molecules ranging from 1 to 75 kbp in size.…”

Section: 5mentioning

confidence: 99%

Euglena Transcript Processing

McWatters

Russell

2017

Advances in Experimental Medicine and Biology

View full text Add to dashboard Cite

RNA transcript processing is an important stage in the gene expression pathway of all organisms and is subject to various mechanisms of control that influence the final levels of gene products. RNA processing involves events such as nuclease-mediated cleavage, removal of intervening sequences referred to as introns and modifications to RNA structure (nucleoside modification and editing). In Euglena, RNA transcript processing was initially examined in chloroplasts because of historical interest in the secondary endosymbiotic origin of this organelle in this organism. More recent efforts to examine mitochondrial genome structure and RNA maturation have been stimulated by the discovery of unusual processing pathways in other Euglenozoans such as kinetoplastids and diplonemids. Eukaryotes containing large genomes are now known to typically contain large collections of introns and regulatory RNAs involved in RNA processing events, and Euglena gracilis in particular has a relatively large genome for a protist. Studies examining the structure of nuclear genes and the mechanisms involved in nuclear RNA processing have revealed that indeed Euglena contains large numbers of introns in the limited set of genes so far examined and also possesses large numbers of specific classes of regulatory and processing RNAs, such as small nucleolar RNAs (snoRNAs). Most interestingly, these studies have also revealed that Euglena possesses novel processing pathways generating highly fragmented cytosolic ribosomal RNAs and subunits and non-conventional intron classes removed by unknown splicing mechanisms. This unexpected diversity in RNA processing pathways emphasizes the importance of identifying the components involved in these processing mechanisms and their evolutionary emergence in Euglena species.

show abstract

Unusual Mitochondrial Genome Structures throughout the Euglenozoa

Cited by 51 publications

References 46 publications

The Mitochondrion of Euglena gracilis

The Mitochondrion of Euglena gracilis

Enzymatic Mechanism Controls Redox-mediated Protein-DNA Interactions at the Replication Origin of Kinetoplast DNA Minicircles

Euglena Transcript Processing

Contact Info

Product

Resources

About