Macronuclear DNA demethylation is involved in the encystment process of the ciliate <i>Colpoda inflata</i>.

Palacios, G

doi:10.1006/cbir.1994.1067

Cited by 19 publications

(8 citation statements)

References 10 publications

(15 reference statements)

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“…On the other hand, Oxytricha uses de novo cytosine methylation for DNA elimination during conjugation[ 30 ]. Apart from these examples, two more ciliates have been reported to possess cytosine methylation in their genomes[ 50 ], [ 51 ]. However, in none of the cases, has the cognate DNA methyltransferase been identified.…”

Section: Discussionmentioning

confidence: 99%

Determination of the presence of 5-methylcytosine in Paramecium tetraurelia

et al. 2018

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5-methylcytosine DNA methylation regulates gene expression and developmental programming in a broad range of eukaryotes. However, its presence and potential roles in ciliates, complex single-celled eukaryotes with germline-somatic genome specialization via nuclear dimorphism, are largely uncharted. While canonical cytosine methyltransferases have not been discovered in published ciliate genomes, recent studies performed in the stichotrichous ciliate Oxytricha trifallax suggest de novo cytosine methylation during macronuclear development. In this study, we applied bisulfite genome sequencing, DNA mass spectrometry and antibody-based fluorescence detection to investigate the presence of DNA methylation in Paramecium tetraurelia. While the antibody-based methods suggest cytosine methylation, DNA mass spectrometry and bisulfite sequencing reveal that levels are actually below the limit of detection. Our results suggest that Paramecium does not utilize 5-methylcytosine DNA methylation as an integral part of its epigenetic arsenal.

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Section: Discussionmentioning

confidence: 99%

Determination of the presence of 5-methylcytosine in Paramecium tetraurelia

et al. 2018

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“…DNA methylation was initially thought to have been lost in ciliates: early investigations found that methylcytosine was undetectable in Tetrahymena , Paramecium , Oxytricha , and Stylonychia . However, reports of methylcytosine's demise in ciliates were greatly exaggerated, as a subsequent study reported methylcytosine in the macronucleus of Blepharisma , and another found a role for methylcytosine during encystment of Colpoda . Even the reported absence of methylcytosine in Stylonychia proved short‐lived, as a study showed evidence of de novo methylation of cytosine on a germline repetitive element during genome rearrangements .…”

Section: Dueling Dna Methylation Models In Oxytricha and Stylonychiamentioning

confidence: 99%

Beyond transcriptional silencing: Is methylcytosine a widely conserved eukaryotic DNA elimination mechanism?

Bracht

2014

BioEssays

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Methylation of cytosine DNA residues is a well-studied epigenetic modification with important roles in formation of heterochromatic regions of the genome, and also in tissue-specific repression of transcription. However, we recently found that the ciliate Oxytricha uses methylcytosine in a novel DNA elimination pathway important for programmed genome restructuring. Remarkably, mounting evidence suggests that methylcytosine can play a dual role in ciliates, repressing gene expression during some life-stages and directing DNA elimination in others. In this essay, I describe these recent advances in the DNA methylation field and discuss whether this unexpected novel role for methylcytosine in DNA elimination might be more widely conserved in eukaryotic biology, particularly in apoptotic pathways.

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“…Total DNA extraction from Colpoda at specific times during encystment was carried out according to the protocol of Palacios et al (1994). One microgram of total DNA was loaded and electrophoresed on 0.8% agarose gel and stained with ethidium bromide.…”

Section: Dna Isolation and Agarose Gel Electrophoresismentioning

confidence: 99%

Chromatin extrusion in resting encystment of Colpoda cucullus: A possible involvement of apoptosis‐like nuclear death

Akematsu¹,

Matsuoka²

2008

Cell Biology International

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The extrusion of macronuclear chromatin is a remarkable characteristic during encystment in Colpoda, but the biological significance of this phenomenon has not been fully elucidated. Here we demonstrate that chromatin extrusion occurs with high frequency when encystment was induced by increasing Ca(2+) in growing cells in various stages of the cell cycle. The Feulgen-DNA reaction revealed that vegetatively growing cells have more macronuclear DNA than cells in the stationary phase, suggesting an association of macronuclear DNA content with the execution of chromatin extrusion. Using 4',6-diamidino-2-phenylindole (DAPI), we found that the size of the macronuclear extrusion body was reduced with time and eventually disappeared approximately 24h after encystment induction. In addition, oligonucleosome-sized DNA cleavage was confirmed to occur concomitant with the size reduction, suggesting that the extrusion body is selectively degraded, while the normal macronucleus remains alive. Combined use of acridine orange and Hoechst 33342 demonstrated that the extruded body was increasingly acidified before final resorption. These features are reminiscent of the nuclear degradation process in conjugating Tetrahymena, and therefore we conclude that chromatin extrusion in Colpoda might occur to adjust the macronuclear DNA content prior to encystment. In this way, it is similar to the apoptotic-like nuclear death that occurs during the conjugation of other ciliates.

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Macronuclear DNA demethylation is involved in the encystment process of the ciliate Colpoda inflata.

Cited by 19 publications

References 10 publications

Determination of the presence of 5-methylcytosine in Paramecium tetraurelia

Determination of the presence of 5-methylcytosine in Paramecium tetraurelia

Beyond transcriptional silencing: Is methylcytosine a widely conserved eukaryotic DNA elimination mechanism?

Chromatin extrusion in resting encystment of Colpoda cucullus: A possible involvement of apoptosis‐like nuclear death

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