Chromatin diminution in nematode development

Tobler, Heinz; Etter, Adrian; Müller, Fritz

doi:10.1016/0168-9525(92)90326-y

Cited by 54 publications

(38 citation statements)

References 22 publications

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“…The repeatability of our technique argues against measurement error (see above). As regards the second and third possibilities, we can exclude only chromosomal diminution of the sort found in ascarids because diploid larval nuclei have been detected in all species studied here (data not shown); chromosomal diminution has, in any case, not been found in C. elegans or in any other free-living nematode so far (36).…”

Section: Resultsmentioning

confidence: 99%

Somatic polyploidization and cellular proliferation drive body size evolution in nematodes

Flemming

Shen

Cunha

et al. 2000

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

142

189

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Most of the hypodermis of a rhabditid nematode such as Caenorhabditis elegans is a single syncytium. The size of this syncytium (as measured by body size) has evolved repeatedly in the rhabditid nematodes. Two cellular mechanisms are important in the evolution of body size: changes in the numbers of cells that fuse with the syncytium, and the extent of its acellular growth. Thus nematodes differ from mammals and other invertebrates in which body size evolution is caused by changes in cell number alone. The evolution of acellular syncytial growth in nematodes is also associated with changes in the ploidy of hypodermal nuclei. These nuclei are polyploid as a consequence of iterative rounds of endoreduplication, and this endocycle has evolved repeatedly. The association between acellular growth and endoreduplication is also seen in C. elegans mutations that interrupt transforming growth factor-␤ signaling and that result in dwarfism and deficiencies in hypodermal ploidy. The transforming growth factor-␤ pathway is a candidate for being involved in nematode body size evolution.

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Section: Resultsmentioning

confidence: 99%

Somatic polyploidization and cellular proliferation drive body size evolution in nematodes

Flemming

Shen

Cunha

et al. 2000

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

142

189

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“…That the majority of adult cerebral neurons display chromosome changes was quite unexpected. Chromosomal or DNA deletions occur in the early development of some animals, such as the nematode Ascaris megalocephala (Boveri, 1887;Tobler et al, 1992), the fly Sciara coprophila (Metz and Schmauck, 1931;Gerbim, 1986), the copepod (Cyclops divulsus) (Beermann, 1977), and the jawless hagfish (Nakai et al, 1991). These deletions usually occur during early embryonic cleavage and appear to facilitate the separation of the germ-cell line from the somatic-cell lineage (Di Berardino, 1997).…”

Section: Discussionmentioning

confidence: 99%

Adult murine neurons: their chromatin and chromosome changes and failure to support embryonic development as revealed by nuclear transfer

Osada

Kusakabe

Akutsu

et al. 2002

Cytogenet Genome Res

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Fully differentiated neurons in adult mammalian brains do not divide; consequently, their metaphase chromosomes have never been examined. Here we report metaphase chromosome constitutions of cortical neurons in adult mice visualized by a nuclear transfer technique. We found that although some reconstructed oocytes cloned from neuronal nuclei have an apparently normal karyotype, the majority do not. Regardless of chromosome morphology, nuclei of adult neurons totally lack the ability to support embryonic development. These findings support the hypothesis that fully differentiated neurons in adult mammalian brains are genomically altered.

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“…A classic example is the heterochromatization of the inactivated X chromosome in female mammals (35). DNA sequences within heterochromatin can also be actively eliminated during somatic development, as occurs in a variety of organisms including species of protozoans, nematodes, crustaceans, insects, and fish (3,15,36,39,40,48). In fact, heterochromatic DNAs are disproportionately or exclusively targeted in most, if not all, cases of chromosome diminution.…”

mentioning

confidence: 99%

The Structure of Heterochromatic DNA Is Altered in Polyploid Cells of Drosophila melanogaster

Glaser

Leach

Ostrowski

1997

Molecular and Cellular Biology

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DNA sequences within heterochromatin are often selectively underrepresented during development of polyploid chromosomes, and DNA molecules of altered structure are predicted to form as a consequence of the underrepresentation process. We have identified heterochromatic DNAs of altered structure within sequences that are underrepresented in polyploid cells of Drosophila melanogaster. Specifically, restriction fragments that extend into centric heterochromatin of the minichromosome Dp(1;f)1187 are shortened in polyploid cells of both the ovary and salivary gland but not in the predominantly diploid cells of the embryo or larval imaginal discs and brains. Shortened DNA molecules were also identified within heterochromatic sequences of chromosome III. These results suggest that the structure of heterochromatic DNA is altered as a general consequence of polyploid chromosome formation and that the shortened molecules identified form as a consequence of heterochromatic underrepresentation. Finally, alteration of heterochromatic DNA structure on Dp(1;f)1187 was not correlated with changes in the variegated expression of the yellow gene located on the minichromosome.

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Chromatin diminution in nematode development

Cited by 54 publications

References 22 publications

Somatic polyploidization and cellular proliferation drive body size evolution in nematodes

Somatic polyploidization and cellular proliferation drive body size evolution in nematodes

Adult murine neurons: their chromatin and chromosome changes and failure to support embryonic development as revealed by nuclear transfer

The Structure of Heterochromatic DNA Is Altered in Polyploid Cells of Drosophila melanogaster

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