Macronuclear DNA in <i>Stentor coeruleus</i>: a first approach to its characterization

Pelvat, B; Haller, G. de

doi:10.1017/s0016672300016463

Cited by 13 publications

(12 citation statements)

References 42 publications

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“…It is important to note that contigs could lie outside the range we identified experimentally. The size of the Stentor genome has previously been estimated at approximately 92Mb [7], similar to our estimate of 83 Mb. Considering the high level of alignment of cDNA reads with our genome (see below) we suspect that our assembly is mostly complete and that the biochemical estimates may have overestimated genome size slightly.…”

Section: Resultssupporting

confidence: 86%

“…The contig size distribution is consistent with prior biochemical analysis of isolated Stentor genomic DNA, in which it was estimated that 50% of the genome consisted of chromosomes in the 46–62 kb range [7]. We further investigated the distribution of chromosome sizes using a CHEF gel (Figure S1 D) and found that the range of sizes is 20kb – 250kb, comparable to the range of sizes of contigs in the assembly (250b–265kb).…”

Section: Resultssupporting

confidence: 82%

“…The genome size is comparable to that of other ciliates (Table S1). The GC content of our assembly is 30%, comparable to the prior biochemical estimate of 32% [7]. …”

Section: Resultssupporting

confidence: 81%

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The Macronuclear Genome of Stentor coeruleus Reveals Tiny Introns in a Giant Cell

et al. 2017

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Summary The giant, single-celled organism Stentor coeruleus has a long history as a model system for studying pattern formation and regeneration in single cells. Stentor (Figure 1A,B [1,2]) is a heterotrichous ciliate distantly related to familiar ciliate models such as Tetrahymena or Paramecium. The primary distinguishing feature of Stentor is its incredible size: a single cell is 1 millimeter long. Early developmental biologists, including T.H. Morgan[3], were attracted to the system because of its regenerative abilities -- if large portions of a cell are surgically removed, the remnant reorganizes into a normal-looking but smaller cell with correct proportionality [2,3]. These biologists were also drawn to Stentor because it exhibits a rich repertoire of behaviors, including light avoidance, mechanosensitive contraction, food selection, and even the ability to habituate to touch, a simple form of learning usually seen in higher organisms [4]. While early microsurgical approaches demonstrated a startling array of regenerative and morphogenetic processes in this single-celled organism, Stentor was never developed as a molecular model system. We report the sequencing of the Stentor coeruleus macronuclear genome and reveal key features of the genome: First, we find that Stentor uses the standard genetic code, suggesting that ciliate specific genetic codes arose after Stentor branched from other ciliates. We also discover that ploidy correlates with Stentor’s cell size. Finally, in the Stentor genome, we discover the smallest spliceosomal introns reported for any species. The sequenced genome opens the door to molecular analysis of single-cell regeneration in Stentor.

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Section: Resultssupporting

confidence: 86%

Section: Resultssupporting

confidence: 82%

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The Macronuclear Genome of Stentor coeruleus Reveals Tiny Introns in a Giant Cell

et al. 2017

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“…DNA was isolated by a modification of Pelvat's method (Pelvat and DeHaller 1976). Cells were washed by photodispersal by, a modification of a method originally described by Dr. Vance Tartar (Tartar, 1961).…”

Section: Methodsmentioning

confidence: 99%

Partial Cloning of Putative G‐Proteins Modulating Mechanotransduction in the Ciliate Stentor

Marino

Sherman

Wood

2001

J Eukaryotic Microbiology

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Signal transduction systems known to utilize G-proteins in higher eukaryotes undoubtedly evolved prior to the development of metazoa. Pharmacological evidence indicates that the ciliates Paramecium, Stentor, and Tetrahymena all utilize signaling systems similar to those found in mammals. However, there has been relatively little direct evidence for the existence of G-proteins in ciliates. Since highly conserved heterotrimeric G-proteins form the basis of receptor-coupled signal transduction systems in a wide variety of metazoa, it is of interest to know if these important signaling molecules were early to evolve and are present and functionally important in a wide variety of unicellular organisms. We have previously shown that mechanotransduction in Stentor is modulated by opiates in a manner that may involve pertussis toxin-sensitive G-proteins. Here we utilize drugs known to interact with G-proteins to further test for the involvement of these important signaling molecules in Stentor mechanotransduction. We present behavioral and electrophysiological data demonstrating that putative G-proteins in Stentor decrease mechanical sensitivity by modulating the mechanotransduction process. In addition, we report the partial cloning of 4 G-protein alpha-subunits from Stentor. We confirm that these clones are of Stentor origin and are transcribed. Furthermore, we employ antisense oligodeoxynucleotide-mediated knockout to demonstrate that these ciliate G-proteins exert a modulatory influence on Stentor behavior, and that a G1/G0-like clone mediates the inhibitory action of beta-endorphin on mechanotransduction.

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“…The macronuclear DNA of Stentor coeruleus (order Heterotrichida and separated from Tetrahymena species and hypotrichs by very large genetic distances) appears to occur in subchromosomal fragments. Most DNA ranges from 7.5 to 60 kbp as determined by sucrose gradients and 45 to 75 kbp by electron microscopy (261). Macronuclear DNA in two cyrtophorid ciliates, Trithigmostoma and Chilodonella species, which are very distant relatives of hypotrichs, ranges in size from 0.35 to -70 kbp with an average size of 4 kbp and with numerous bands in electrophoretic gels, presumably representing particular, differentially amplified molecules (195,229).…”

Section: Micronuclear and Macronuclear Dnasmentioning

confidence: 99%