DNA sequence organization in the alga Euglena gracilis

Rawson, James R.Y.; Eckenrode, Virginia K.; Boerma, Cindy L.; Curtis, S. E.

doi:10.1016/0005-2787(79)90002-9

Cited by 14 publications

(5 citation statements)

References 28 publications

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“…The intense nuclear staining in Euglena compared to T.brucei is not surprising, since Euglena diploid nuclei contain 3.0 pg DNA (22) and T.brucei nuclei only 0.1 pg (23). In T.brucei, a substantial fraction of J is in the telomeric (GGGTTA) n repeats (24) and this is also evident from the pictures in Figure 2 that show that part of the punctate J staining coincides with the punctate staining of the clustered telomeres of T.brucei.…”

Section: Resultsmentioning

confidence: 96%

Base J originally found in Kinetoplastida is also a minor constituent of nuclear DNA of Euglena gracilis

Dooijes

Chaves²,

Kieft³

et al. 2000

Nucleic Acids Research

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We have analyzed DNA of EUGLENA: gracilis for the presence of the unusual minor base beta-D-glucosyl-hydroxymethyluracil or J, thus far only found in kinetoplastid flagellates and in DIPLONEMA: Using antibodies specific for J and post-labeling of DNA digests followed by two-dimensional thin-layer chromatography of labeled nucleotides, we show that approximately 0.2 mole percent of EUGLENA: DNA consists of J, an amount similar to that found in DNA of Trypanosoma brucei. By staining permeabilized EUGLENA: cells with anti-J antibodies, we show that J is rather uniformly distributed in the EUGLENA: nucleus, and does not co-localize to a substantial extent with (GGGTTA)(n) repeats, the putative telomeric repeats of EUGLENA: Hence, most of J in EUGLENA: appears to be non-telomeric. Our results add to the existing evidence for a close phylogenetic relation between kinetoplastids and euglenids.

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Section: Resultsmentioning

confidence: 96%

Base J originally found in Kinetoplastida is also a minor constituent of nuclear DNA of Euglena gracilis

Dooijes

Chaves²,

Kieft³

et al. 2000

Nucleic Acids Research

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“…The Olisthodiscus genome is composed of 45% repeat DNA sequences. This amount of middle repetitive DNA is also seen in similar proportion in two other algae (Rawson et al, 1979;Hinnebusch et al, 1980) with high nuclear DNA content, namely, Euglena gracilis and Crypthicodinium cohnii, but is minimal (Bayen & Dalmon, 1975; Prima et al, 1974;Howell & Walker, 1976;Siu et al, 1974) in Chlorella pyrenoidosa, Chlorella vulgaris, Chlamydomonas reinhardtii, and Polytoma obtusum, whose small genomes have virtually no (except for rRNA cistrons) repeat sequences. Since these seven organisms represent the entire literature of DNA sequence organization studies of algal cells, it is premature to initiate an evolutionary (Eden & Hendrick, 1978) or genomic size (Hutchinson et al, 1980;Thompson & Murray, 1980) comparison as possible factors effecting repeated DNA distribution, for these organisms represent four different phyla and have almost an 80-fold difference in haploid DNA content.…”

Section: Resultsmentioning

confidence: 81%

“…However, it must be noted that although in low number, repeated segments do exist which are long enough to occupy a major portion of a 3000 base pair DNA fragment. This information places Olisthodiscus among the few unicellular algae, most of which are chlorophytes (Bayen & Dalmon, 1975; Rawson et al, 1979;Howell & Walker, 1976;Siu et al, 1974;Roberts et al, 1974) for which genome size is reliably known. It is interesting to note that a cellular DNA content such as that observed in Olisthodiscus is not unique among the chromophytic algae.…”

Section: Resultsmentioning

confidence: 99%

Nuclear deoxyribonucleic acid characterization of the marine chromophyte Olisthodiscus luteus

Ersland¹,

Cattolico²

1981

Biochemistry

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Nuclear DNA of the marine chromophytic alga Olisthodiscus luteus was analyzed in this study. Reassociation kinetics analysis has shown that 440-nucleotide DNA fragments from the genome of this alga contain 4% foldback, 58% repetitive, and 34% single-copy sequences. Precise analysis using isolated single-copy DNA revealed that Olisthodiscus has a large haploid DNA content of 1.66 x 10(-12) g/cell. For determination of the organization of single-copy and repetitive sequences within this genome, DNA fragments 3000 nucleotides in length were reassociated to C0t= 100 M . s. At this low C0t value 89% of the DNA bound to hydroxylapatite, suggesting that single-copy and repetitive elements are interspersed. The lengths of the duplexed repetitive DNA on these 3000-nucleotide fragments were measured by electron microscopy after digestion with S1 nuclease which removed the unreassociated single-copy DNA regions. Of these repetitive sequences, 68% were shorter than 1200 nucleotide pairs in length and had a modal length of 350 nucleotide pairs. A minor class of longer (to 4000 nucleotide pairs) repetitive sequences was also observed.

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“…Euglenoid flagellates have condensed chromosomes in interphase and throughout the mitotic cycle (Leedale, , ; Gillott & Triemer, ), consistent with the finding that the majority of the genome contains non‐coding DNA that is not transcribed (Ebenezer et al, , ). The large fraction of repetitive DNA (65%) and relatively high proportion of foldback DNA (14%) may be responsible for the continually condensed structure of the Euglena chromosomes (Rawson et al, ). Permanently condensed heterochromatin was recently observed also in diplonemids (Tashyreva et al, ).…”

Section: Euglenozoan Nuclear Genomesmentioning

confidence: 99%

Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa

et al. 2019

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Parasitic trypanosomatids and phototrophic euglenids are among the most extensively studied euglenozoans. The phototrophic euglenid lineage arose relatively recently through secondary endosymbiosis between a phagotrophic euglenid and a prasinophyte green alga that evolved into the euglenid secondary chloroplast. The parasitic trypanosomatids (i.e. Trypanosoma spp. and Leishmania spp.) and the freshwater phototrophic euglenids (i.e. Euglena gracilis) are the most evolutionary distant lineages in the Euglenozoa phylogenetic tree. The molecular and cell biological traits they share can thus be considered as ancestral traits originating in the common euglenozoan ancestor. These euglenozoan ancestral traits include common mitochondrial presequence motifs, respiratory chain complexes containing various unique subunits, a unique ATP synthase structure, the absence of mitochondria‐encoded transfer RNAs (tRNAs), a nucleus with a centrally positioned nucleolus, closed mitosis without dissolution of the nuclear membrane and nucleoli, a nuclear genome containing the unusual ‘J’ base (β‐D‐glucosyl‐hydroxymethyluracil), processing of nucleus‐encoded precursor messenger RNAs (pre‐mRNAs) via spliced‐leader RNA (SL‐RNA) trans‐splicing, post‐transcriptional gene silencing by the RNA interference (RNAi) pathway and the absence of transcriptional regulation of nuclear gene expression. Mitochondrial uridine insertion/deletion RNA editing directed by guide RNAs (gRNAs) evolved in the ancestor of the kinetoplastid lineage. The evolutionary origin of other molecular features known to be present only in either kinetoplastids (i.e. polycistronic transcripts, compaction of nuclear genomes) or euglenids (i.e. monocistronic transcripts, huge genomes, many nuclear cis‐spliced introns, polyproteins) is unclear.

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DNA sequence organization in the alga Euglena gracilis

Cited by 14 publications

References 28 publications

Base J originally found in Kinetoplastida is also a minor constituent of nuclear DNA of Euglena gracilis

Base J originally found in Kinetoplastida is also a minor constituent of nuclear DNA of Euglena gracilis

Nuclear deoxyribonucleic acid characterization of the marine chromophyte Olisthodiscus luteus

Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa

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