Susceptibility of heterochromatin to aphidicolin-induced chromosomal breakage

Domínguez, Ana; Smith, Scott C.; Greenbaum, Ira F.

doi:10.1007/bf00197404

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…The standardized Χ 2 (Χ 2 s ) test statistic was used for all fragile site identifications. As the autosomal heterochromatin of Peromyscus has been shown to be highly resistant to APC-induced chromosomal breakage (Dominguez et al 1995) and as breaks were not observed in the autosomal heterochromatin of the individuals examined, these regions were excluded from the analysis. Each of the G-bands from the included regions was considered to make an equal contribution to the genome.…”

Section: Methodsmentioning

confidence: 99%

How common are common fragile sites: variation of aphidicolin-induced chromosomal fragile sites in a population of the deer mouse ( Peromyscus maniculatus )

McAllister

Greenbaum

1997

Human Genetics

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Aphidicolin (APC)-induced chromosomal gaps and breaks were analyzed for ten deer mice (Peromyscus maniculatus) from a natural population. The FSM statistical methodology was used to identify fragile sites as chromosomal loci exhibiting significantly non-random numbers of gaps/breaks in each individual and enabled an assessment of variation in fragile sites among the individuals. The individual deer mice exhibited as few as 7 to as many as 19 of the populational total of 34 sites. Two sites were fragile in all individuals and 13 sites were fragile in single individuals only. Defined by populational frequencies of greater than 50%, high-frequency fragile sites constituted 26% of the populational total. Approximately 35% of the total fragile sites were fragile in 20-40% of the population (low-frequency fragile sites) and about 38% were fragile in single individuals only. Analysis of the data pooled over all individuals identified significantly non-random breakage at 80 sites, 47 of which were not identified as fragile in any single individual. It appears, therefore, that fragile site identifications from pooled data have fostered an inflated estimate of the numbers and frequencies of common fragile sites. Comparison of the fragile site and spontaneous breakage (control) data suggest that APC-induced fragile sites represent regions of chromosomes that experience elevated levels of somatic mutation. Additionally, the occurrence of APC-induced fragile sites at or near the interstitial breakpoints of two pericentric-inversion polymorphisms in this population supports the hypothesis that fragile sites experience an increased rate of meiotic chromosomal mutation and are predisposed to undergo phylogenetic rearrangement.

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Section: Methodsmentioning

confidence: 99%

How common are common fragile sites: variation of aphidicolin-induced chromosomal fragile sites in a population of the deer mouse ( Peromyscus maniculatus )

McAllister

Greenbaum

1997

Human Genetics

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“…With the exception of three distinct bands in the short arm of Chr X in P. eremicus, however, this same probe did not hybridize to noncentromeric heterochromatin of the X or Y chromosome. Further, although Dominguez (1991) showed that the autosomal heterochromatin of Peromyscus is highly resistant to aphidicolin-induced breakage. McAllister (1992) documented the existence of an aphidicolin-induced fragile site in the heterochromatic arm of Chr X in P. maniculatus.…”

Section: Sex Heterochromatinmentioning

confidence: 99%

Cytogenetic nomenclature of deer mice, <i>Peromyscus </i>(Rodentia): revision and review of the standardized karyotype

Greenbaum

Gunn²,

Smith³

et al. 1994

Cytogenet Genome Res

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A revision of the standardized karyotype of deer mice (Peromyscus) is presented. This revision addresses shortcomings of the original standardization, contains a substantial increase in the number of G-band markers and provides a nomenclature for the G-bands of each autosome and the X chromosome. Using the revised standardized karyotype, we specify the particular G-bands or patterns that identify each chromosome and catalog the more problematic chromosome identifications and likely misidentifications. For each chromosome, we present an overview of previously reported variation in euchromatic arrangement and heterochromatic constitution. We then review previous applications of the standardized karyotype and summarize the predominant findings from cytogenetic and cytosystematic studies of Peromyscus and related taxa.

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“…These types of microsatellite sequences have been found in non-exon areas of the genes and their role in the human genome remains enigmatic. The resistance of autosomal heterochromatin of Peromyscus to aphidicolin-induced chromosomal breakage [Dominiguez et al, 1995] argue against a simple relationship between late replication and a general mechanism for chromosomal fragility. Our study was too limited to evaluate individual fragile site expression statistically, but clearly not all the sites evaluated were expressed with higher frequencies in RS when compared to age matched controls.…”

Section: Discussionmentioning

confidence: 95%

Additional Clinical and Cytogenetic Findings Associated With Rett Syndrome

Simonic

Gericke

Lippert³

et al. 1997

Am. J. Med. Genet.

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An analysis of all aphidicolin-inducible breakpoints has been carried out in PHA stimulated T-lymphocytes of five patients with classical Rett syndrome, their mothers and a group of age matched controls. Observed breakpoints were divided into two groups: common, rare, and those recorded by others but not assigned as fragile sites by CCM92 and a group of non-specified breakpoints recurrently found in our ongoing study of fragile sites. In addition cooccurrence of trisomy X in one patient and de novo pericentromeric inversion on chromosome 2 in another Rett syndrome patient are reported. The co-occurrence with the Tourette syndrome in two of our families, and the fact that both Rett and Tourette syndrome are associated with movement disorders, possible dopaminergic hypersensitivity and increased chromosomal fragility in subsets of fragile sites, may suggest a possible avenue for further research. The cytogenetic findings indicate that both X-linked and autosomal regulatory region(s) may be part of a complex genetic alteration in association with Rett syndrome.

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Susceptibility of heterochromatin to aphidicolin-induced chromosomal breakage

Cited by 4 publications

References 28 publications

How common are common fragile sites: variation of aphidicolin-induced chromosomal fragile sites in a population of the deer mouse ( Peromyscus maniculatus )

How common are common fragile sites: variation of aphidicolin-induced chromosomal fragile sites in a population of the deer mouse ( Peromyscus maniculatus )

Cytogenetic nomenclature of deer mice, <i>Peromyscus </i>(Rodentia): revision and review of the standardized karyotype

Additional Clinical and Cytogenetic Findings Associated With Rett Syndrome

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