The Nucleus in Differentiation and Development

Duncan, Robert E.; Ross, James G.

doi:10.1093/oxfordjournals.jhered.a106054

Cited by 61 publications

(28 citation statements)

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“…3 that the frequency of callus formation was markedly decreased in the F1 endosperm obtained by the reciprocal crosses between S41 and S43 as compared with that in S41 x S41. In the endosperm obtained by the backcrosses, the occurrence of callus was rare especially These observations are similar to those reported by Randolph (1936) and Duncan and Ross (1950) and indicate that the differences in growth response of endosperm explants between strains or crosses are not ascribed to anatomically visible differences.…”

Section: Genetic Testssupporting

confidence: 89%

HEREDITARY CONTROL OF CALLUS FORMATION IN MAIZE ENDOSPERM CULTURED <i>IN VITRO</i>

Tabata

Motoyoshi

1965

The Japanese journal of genetics

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Section: Genetic Testssupporting

confidence: 89%

HEREDITARY CONTROL OF CALLUS FORMATION IN MAIZE ENDOSPERM CULTURED <i>IN VITRO</i>

Tabata

Motoyoshi

1965

The Japanese journal of genetics

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“…Maize endosperm nuclei were early recognized by their large size (up to 1000 times the volume of diploid nuclei; Duncan and Ross, 1950). Due to a high endoreduplication rate in maize endosperm (up to 690C; Lopes and Larkins, 1993), it is difficult to distinguish between the effects of endoreduplication and chromatin decondensation on nuclear size.…”

Section: The Large Size Of Endosperm Nuclei May Be Attributed To a Lomentioning

confidence: 99%

The Triploid Endosperm Genome ofArabidopsisAdopts a Peculiar, Parental-Dosage-Dependent Chromatin Organization

et al. 2007

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The endosperm is a seed tissue unique to flowering plants. Due to its central role in nourishing and protecting the embryo, endosperm development is subject to parental conflicts and adaptive processes, which led to the evolution of parent-oforigin-dependent gene regulation. The role of higher-order chromatin organization in regulating the endosperm genome was long ignored due to technical hindrance. We developed a combination of approaches to analyze nuclear structure and chromatin organization in Arabidopsis thaliana endosperm. Endosperm nuclei showed a less condensed chromatin than other types of nuclei and a peculiar heterochromatin organization, with smaller chromocenters and additional heterochromatic foci interspersed in euchromatin. This is accompanied by a redistribution of the heterochromatin mark H3K9me1 from chromocenters toward euchromatin and interspersed heterochromatin. Thus, endosperm nuclei have a specific nuclear architecture and organization, which we interpret as a relaxed chromocenter-loop model. The analysis of endosperm with altered parental genome dosage indicated that the additional heterochromatin may be predominantly of maternal origin, suggesting differential regulation of maternal and paternal genomes, possibly linked to genome dosage regulation.

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“…This finding has led to the idea that endoreduplicated chromosomes in the maize endosperm have a polytene-like structure (Kowles and Phillips 1985). It has also been previously noted that as more rounds of endoreduplication occur, the number of deeply staining heterochromatic areas, such as knobs and nuclear organizing regions (NORs), does not change (Duncan and Ross 1950). This observation indicates that even though endoreduplication creates higher ploidy endosperm, the number of chromosomes does not change, but the increase in ploidy is the result of the chromatids endoreduplicating, giving the wide chromatid appearance.…”

Section: Introductionmentioning

confidence: 98%

Organization of endoreduplicated chromosomes in the endosperm of Zea mays L

Bauer

Birchler

2006

Chromosoma

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The chromosomes of the maize endosperm proceed through an endoreduplication phase in later stages of development. Endoreduplication is a process in which the cell cycle continues DNA synthesis but does not proceed through cytokinesis. When this occurs, the normally triploid endosperm cell can reach ploidy levels greater than 200x in some lines of maize. In this work, we examined the structure of the endoreduplicated chromosomes. Previous cytological work has indicated that, although the DNA content per cell increases, the number of nucleoli and knobs remains the same. Using fluorescence in situ hybridization and slot blot techniques, we show that the highly repetitive heterochromatic areas both on the A and B chromosomes, as well as several actively transcribed genes, are endoreduplicated. This result suggests that the entire genome follows that same trend. Further evidence shows that the various chromatin strands stay associated throughout the length of the chromosomes after they have been replicated, and that the DNA at the centromeric and knob regions is more tightly associated than the other regions of the chromosomes. Interploidy crosses between diploid and tetraploid derivatives of the same inbred exhibit changes in the chromatin organization of centromeres and heterochromatic knobs.

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The Nucleus in Differentiation and Development

Cited by 61 publications

References 0 publications

HEREDITARY CONTROL OF CALLUS FORMATION IN MAIZE ENDOSPERM CULTURED <i>IN VITRO</i>

HEREDITARY CONTROL OF CALLUS FORMATION IN MAIZE ENDOSPERM CULTURED <i>IN VITRO</i>

The Triploid Endosperm Genome ofArabidopsisAdopts a Peculiar, Parental-Dosage-Dependent Chromatin Organization

Organization of endoreduplicated chromosomes in the endosperm of Zea mays L

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