Cell lineage and its consequences in higher plants

Dawe, R. Kelly; Freeling, Michael

doi:10.1111/j.1365-313x.1991.00003.x

Cited by 72 publications

(20 citation statements)

References 45 publications

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“…However, an alternative possibility is that a small number of meristem cells, possibly the slowly dividing cells in the central zone of the shoot apical meristem (Medford 1992), were not affected by aza-dC. Over time, clonal descendants of these unaffected cells might fully occupy the central and peripheral zones of the meristems in older plants (Dawe and Freeling 1991), giving rise to vegetative organs whose cells contain fully methylated nuclear DNA. At present we are unable to distinguish between these possibilities.…”

Section: The Derepressed State Of Under-dominant Rrna Genes Is Unstablementioning

confidence: 99%

Epigenetic silencing of RNA polymerase I transcription: a role for DNA methylation and histone modification in nucleolar dominance

Zj¹,

Pikaard²

1997

Genes Dev.

356

262

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Nucleolar dominance is an epigenetic phenomenon that describes nucleolus formation around rRNA genes inherited from only one progenitor of an interspecific hybrid or allopolyploid. The phenomenon is widespread, occurring in plants, insects, amphibians, and mammals, yet its molecular basis remains unclear. We have demonstrated nucleolar dominance in three allotetraploids of the plant genus Brassica. In Brassica napus, accurately initiated pre-rRNA transcripts from one progenitor, Brassica rapa are detected readily, whereas transcripts from the ∼3000 rRNA genes inherited from the other progenitor, Brassica oleracea, are undetectable. Nuclear run-on confirmed that dominance is controlled at the level of transcription. Growth of B. napus seedlings on 5-aza-2-deoxycytidine to inhibit cytosine methylation caused the normally silent, under-dominant B. oleracea rRNA genes to become expressed to high levels. The histone deacetylase inhibitors sodium butyrate and trichostatin A also de-epressed silent rRNA genes. These results reveal an enforcement mechanism for nucleolar dominance in which DNA methylation and histone modifications combine to regulate rRNA gene loci spanning tens of megabase pairs of DNA.

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Section: The Derepressed State Of Under-dominant Rrna Genes Is Unstablementioning

confidence: 99%

Epigenetic silencing of RNA polymerase I transcription: a role for DNA methylation and histone modification in nucleolar dominance

Zj¹,

Pikaard²

1997

Genes Dev.

356

262

View full text Add to dashboard Cite

show abstract

“…Clonal analysis of chimeric markers in several plant species has demonstrated that cell fate in plants is determined primarily by position and relies little on cell lineage (Poethig et al, 1986;Jegla and Sussex, 1989;Dawe and Freeling, 1991). The establishment of a complex vascular system offers a particularly striking example of the precision with which these positional signals must be controlled, because plant cells do not migrate relative to each other during development.…”

Section: Introductionmentioning

confidence: 99%

Genetic Regulation of Vascular Tissue Patterning in Arabidopsis

et al. 1999

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Plants transport water and nutrients through a complex vascular network comprised of interconnected, specialized cell types organized in discrete bundles. To identify genetic determinants of vascular tissue patterning, we conducted a screen for mutants with altered vascular bundle organization in Arabidopsis cotyledons. Mutations in two genes, CVP1 and CVP2 (for cotyledon vascular pattern), specifically disrupt the normal pattern of vascular bundles in cotyledons, mature leaves, and inflorescence stems. The spatial distribution of the procambium, the precursor to mature vascular tissue, is altered in cvp1 and cvp2 embryos, suggesting that CVP1 and CVP2 act at a very early step in vascular patterning. Similarly, in developing stems of cvp1 and leaves of cvp2 , the pattern of vascular differentiation is defective, but the maturation of individual vascular cells appears to be normal. There are no discernible alterations in cell morphology in cvp2 mutants. In contrast, cvp1 mutants are defective in directional orientation of the provascular strand, resulting in a failure to establish uniformly aligned vascular cells, and they also show a reduction in vascular cell elongation. Neither cvp1 nor cvp2 mutants displayed altered auxin perception, biosynthesis, or transport, suggesting that auxin metabolism is not generally affected in these mutants.

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“…We wanted to understand how this variegation was passed to the ear shoots whose founder cells intersect the borders between the two contrasting phenotypes. Sector boundary analysis first proposed by Sturtevant (1929), and discussed for plants by Dawe and Freeling (1991) and by Spena and Salamini (1995) was used for analysis. Our results indicate that the cells giving rise to the ear should be few in number.…”

Section: Resultsmentioning

confidence: 99%

The clonal origin of the lateral meristem generating the ear shoot of maize

Uhrig¹,

Marocco

Döring

et al. 1997

Planta

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Abstract. The ear shoot of maize (Zea mays L.) consists of the peduncle and reproductive tissues (ear). Genetic mosaics induced by the unstable allele of the chl locus were used for cell lineage analysis of the ear shoot. The unstable chl-ml allele, caused by the insertion of a transposable element, gives rise to yellow-green seedlings with many small revertant green stripes. Rare plants with large reverrant sectors comprising 30-50% of the plant were selected. Nineteen plants showing large sectors on the main stem were subjected to sector boundary analysis. Sectoring was recorded for the main stem, leaf subtending the ear shoot, peduncle, prophyll and ear. The reproductive part of the ear shoot, the ear, was scored after removal of the husks and subsequent exposure to light. In 18 cases the ear was non-sectored yellow-green or green. In an additional four cases, peduncle cell lineages entered the ear, but only in the proximal part, while the tip of the ear was non-sectored. Two additional ears showed longitudinal sectors which reached the tip of the ear. These observations indicate that in the lateral meristem of the ear shoot two types of cellular clone exist. One will generate the peduncle, the other will found the ear. Sector boundary analysis indicates that for the vegetative part of the ear shoot the number of meristem founder cells is high, whereas only a few initials are recruited for the formation of the ear. The presence of ear sectors not starting in the peduncle and reaching the ear tip, and the finding that the ear is frequently non-sectored, suggest that this organ derives from an apical type of growth.

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Cell lineage and its consequences in higher plants

Cited by 72 publications

References 45 publications

Epigenetic silencing of RNA polymerase I transcription: a role for DNA methylation and histone modification in nucleolar dominance

Epigenetic silencing of RNA polymerase I transcription: a role for DNA methylation and histone modification in nucleolar dominance

Genetic Regulation of Vascular Tissue Patterning in Arabidopsis

The clonal origin of the lateral meristem generating the ear shoot of maize

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