Patterns of heterochromatin distribution in plant chromosomes

Guerra, Marcelo

doi:10.1590/s1415-47572000000400049

Cited by 213 publications

(187 citation statements)

References 138 publications

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“…These constrictions are largely known as 45S rDNA location sites, although smaller or less active 45S rDNA sites may exist in chromosomes which apparently do not form secondary constrictions (Guerra et al, 1996). On the other hand, heterochromatic regions are generally identified by either Cbanding techniques or direct staining with base-specific fluorochromes, such as 4-6-diamidino-2-phenylindole (DAPI), Hoechst 33258, chromomycin A3 (CMA), mythramycin, quinacrin, and others ( Schmid and Guttenbach, 1988;Sumner, 1990;Guerra, 2000). The reaction of these fluorochromes with the chromosomes depends mainly on the nitrogen base composition of the DNA molecule, in such a way that each region of the chromosome may show a positive (+), negative (-) or neutral (0) reaction with a given fluorochrome (Schweizer, 1981).…”

Section: Introductionmentioning

confidence: 99%

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Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

2006

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We investigated four orchids of the genus Maxillaria (M. discolor, M. acicularis, M. notylioglossa and M. desvauxiana) in regard to the position of heterochromatin blocks as revealed using chromomycin A 3 (CMA) and 4'-6-diamidino-2-phenylindole (DAPI) fluorochrome staining and 5S and 45S rDNA sites using fluorescence in situ hybridization (FISH). The species showed differences in chromosome number and a diversified pattern of CMA + and DAPI + bands, including heteromorphism for CMA + bands. The 5S and 45S rDNA sites also varied in number and most of them were co-localized with CMA + bands. The relationship between 5S rDNA sites and CMA + bands was more evident in M. notylioglossa, in which the brighter CMA + bands were associated with large 5S rDNA sites. However, not all 5S and 45S rDNA sites were co-localized with CMA + bands, probably due to technical constraints. We compare these results to banding data from other species and suggest that not all blocks of tandemly repetitive sequences, such as 5S rDNA sites, can be observed as heterochromatin blocks.

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Section: Introductionmentioning

confidence: 99%

“…In plants, the most used fluorochromes are CMA, which preferentially stains GC-rich DNA, and DAPI, which preferentially stains AT-rich regions. Using these two fluorochromes, heterochromatin blocks can be characterized as CMA (Guerra, 2000).…”

Section: Introductionmentioning

confidence: 99%

Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

2006

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“…2), were observed among and within ploidy levels. The size and intensity of AgNORs localized in secondary constrictions have been correlated with the activity of rRNA genes which are transcribed during the previous interphase (Hubbell 1985, Guerra 2000. The size of silver granule dots at metaphase is much smaller than the silver granule dots at interphase because only 10% of the silver stained nucleolar protein during interphase are retained on metaphase chromosomes (Sumner 2003).…”

Section: Discussionmentioning

confidence: 99%

Analysis of Active Nucleolus Organizing Regions in Polyploid Prairie Cordgrass (<i>Spartina pectinata</i> Link) by Silver Staining

2015

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Summary Prairie cordgrass has recently gained attention as an important biotic component of stressed ecosystems. This polyploid species is distributed broadly across the U.S. More cytogenetic data are needed to investigate how increased ploidy levels influence chromosome changes and gene expression in order to understand the formation of stable cytotypes. Silver staining is the cytogenetic method commonly used to study the number and distribution of active nucleolar organizing regions (NORs) on chromosomes at metaphase, and the number and size of nucleoli in nuclei at interphase. Intensity and distribution patterns of silver stained NORs (AgNORs) reveal differential ribosomal gene expressions in plants and animals. The purpose of this study is to estimate the number of AgNORs, their locations, and their activities in metaphase chromosomes and to determine heteromorphic variation in size and number of nucleoli within interphase nuclei for tetra-, hexa-, and octoploid prairie cordgrass populations. Increases in mean numbers of AgNORs in each metaphase and interphase cell were observed as ploidy level increases. Although distribution patterns of silver stained NORs at metaphase cells of tetra-and octoploids reflect changes in ploidy, the neohexaploids did not follow the pattern, indicating that active NORs were not stable in early generation of formation of neo-hexaploidy. Collectively, these results suggest that distribution patterns of silver stained NORs in metaphase and number of silver stained nucleoli in interphase cells can be used as markers to detecting chromosome variations within and among ploidy levels and to determine when ploidy levels stabilize in prairie cordgrass.

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“…Although both techniques reveal constitutive heterochromatin, they differed significantly in the procedures used and in the banding patterns they reveal. While C-banding requires physico-chemical pretreatment, base specific banding depends on the affinity of heterochromatin for a specific fluorochrome (Guerra 2000; Barros e Silva & Guerra 2010).…”

Section: Fluorescence Bandingmentioning

confidence: 99%

Karyotype analysis in two species ofSolanum(Solanaceae) Sect.Cyphomandropsisbased on chromosome banding

Miguel

Acosta

Moscone

2012

New Zealand Journal of Botany

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To contribute to the cytogenetic characterisation of the Cyphomandra clade of Solanum, fluorescence banding and silver staining were performed on Solanum fusiforme and Solanum stuckertii for the first time. Both species had 2n 024 chromosomes. Solanum fusiforme had a karyotype consisting of 9m ' 3sm chromosome pairs; one pair had active nucleolar organiser regions (NORs). Solanum stuckertii had 8m ' 4sm chromosome pairs with two pairs having active NORs. The two species exhibit similar amounts (11%) of constitutive CMA ' /DAPI ( heterochromatin, rich in GC base pairs. This heterochromatin was distributed in a complex pattern of mainly intercalary bands. Localisation of chromosome-specific markers was successful, allowing recognition of all chromosomes of the complements. With the aim of contributing to a better understanding of the interspecific relationships within the Cyphomandra clade, we discuss our results in conjunction with previous findings for species in this clade.

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Patterns of heterochromatin distribution in plant chromosomes

Cited by 213 publications

References 138 publications

Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

Analysis of Active Nucleolus Organizing Regions in Polyploid Prairie Cordgrass (<i>Spartina pectinata</i> Link) by Silver Staining

Karyotype analysis in two species ofSolanum(Solanaceae) Sect.Cyphomandropsisbased on chromosome banding

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