The fate of DNA statellites I, II, III and ribosomal DNA in a familial dicentric chromosome 13:14

Gosden, John R.; Gosden, Christine; Lawrie, Sandra S.; Mitchell, A. R.

doi:10.1007/bf00273095

Cited by 30 publications

(17 citation statements)

References 28 publications

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“…h). These observations are in good agreement with the general absence of NORs on so matic chromosomes that are involved in transloca tions (Hurley and Pathak, 1977;Gosden et al, 1978;Zankl and Hahmann, 1978;Brasch and Smith. 1979;Mattei et al 1979;Mikkelsen et al 1980).…”

Section: Determination O F the Breakpointssupporting

confidence: 79%

Pachytene analysis of a man with a 13q;14q translocation and infertility

Luciani¹,

Guichaoua²,

Mattei³

et al. 1984

Cytogenet Genome Res

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Pachytene analysis was undertaken in a sterile 13q;14q heterozygous translocation carrier in an attempt to follow the segregational behavior of the trivalent and to evaluate the relationship of Robertsonian translocations in man to the impairment of spermatogenesis. Well-spread bivalents from pachytene nuclei were identified by their chromomere patterns. The trivalent was found always in cis configuration. Silver staining demonstrated the loss of nucleolar organizer regions from the translocated chromosomes. A nonrandom association was found between the trivalent configuration and the sex vesicle in 61% of the pachytene nuclei examined. Such an association has been described before in mice heterozygous for Robertsonian or reciprocal translocations, and may thus represent a general phenomenon. As in mice, this contact was restricted to the centromeric region of the trivalent. A hypothesis relating the association of the trivalent with the sex vesicle to impairment of normal X-chromosome inactivation and subsequent spermatogenic breakdown is discussed. Other chromosomal abnormalities in which sex-vesicle anomalies are associated with male sterility (such as X-or Y-autosomal translocations) are also considered. It is proposed that any process interfering with normal X-chromosome inactivation in pachytene spermatocytes could disturb subsequent meiotic or postmeiotic germ-cell development.

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Section: Determination O F the Breakpointssupporting

confidence: 79%

Pachytene analysis of a man with a 13q;14q translocation and infertility

Luciani¹,

Guichaoua²,

Mattei³

et al. 1984

Cytogenet Genome Res

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“…The clones were sequenced from both ends to obtain the sequences of the four dimers shown in the figure. (18,19). Our data suggest that homogenization occurs predominantly on different homologues, establishing independently chromosome-specific subfamilies with different characteristic lengths of sequence register (6,20).…”

Section: Resultsmentioning

confidence: 99%

Homologous subfamilies of human alphoid repetitive DNA on different nucleolus organizing chromosomes.

Jørgensen¹,

Bostock²,

Bak³

1987

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

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The organization of alphoid repeated sequences on human nucleolus-organizing (NOR) chromosomes 13, 21, and 22 has been investigated. Analysis of hybridization of alphoid DNA probes to Southern transfers of restriction enzyme-digested DNA fragments from hybrid cells containing single human chromosomes shows that chromosomes 13 and 21 share one subfamily of alphoid repeats, whereas a different subfamily may be held in common by chromosomes 13 and 22. The sequences of cloned 680-base-pair EcoRI fragments of the alphoid DNA from chromosomes 13 and 21 show that the basic unit of this subfamily is indistinguishable on each chromosome. The sequence of cloned 1020-base-pair Xba I fragments from chromosome 22 is related to, but distinguishable from, that of the 680-base-pair EcoRI alphoid subfamily of chromosomes 13 and 21. These results suggest that, at some point after they originated and were homogenized, different subfamilies of alphoid sequences must have exchanged between chromosomes 13 and 21 and separately between chromosomes 13 and 22.One of the models for genomic change that mediates the evolution of new species or generates major changes within a species involves periodic reorganizations of the genome accompanied by amplification of different families of repetitive DNA. The alphoid family of repetitive DNA is found exclusively in primates and has been studied in human and several monkey and ape species. It is believed that different families of this repeat arose prior to the emergence of several of these species, after which the alphoid families have remained relatively unchanged (1). Although the separation of the branches leading to the great apes and humans took place 6-8 million years ago (2), the most significant human evolution has probably taken place within the last few million years. One might therefore expect to find within the human genome families of the alphoid repeat that have been amplified relatively recently, and evidence for one such family has already been reported (3). Recent studies (4)(5)(6) indicate that human alphoid DNA is organized into chromosome-specific subfamilies, formed by the amplification of segments composed of tandemly arranged related copies of the 170-basepair (bp) (monomeric) or 340-bp (dimeric) repeat units.Chromosome specificity of subfamilies of alphoid DNA implies that transfer of sequences between nonhomologous human chromosomes occurs very rarely. However, one group of chromosomes, the nucleolus organizing (NOR) chromosomes, appears to undergo recombination between nonhomologues more frequently than do other chromosomes (7,8), and thus some alphoid families might be expected to be held in common between the NOR chromosomes. We report here studies on the alphoid repetitive DNA in three different human NOR-bearing chromosomes-13, 21, and 22. These chromosomes hold in common a related subfamily of alphoid sequences that has diverged =25% from the average sequence of alphoid repeats. The sequences of tetramers of the basic unit of this alphoid family are indisti...

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“…In dicentric Robertsonian translocations, satellite DNA can be detected in association with each centromere, but its quantity is almost always less than that associated with the normal homolog's centromere. Because in most cases neither rDNA nor silver-positive NORs can be detected (4), the break points must almost always be within the region containing satellite DNA-i.e., between the centromere and the NOR (8). In monocentric translocations, no satellite DNA can be found in the chromosome arm that has lost its centromere.…”

Section: Spermatogonia and Spermatocytesmentioning

confidence: 99%

“…Nonhomologous chromosomes are involved in 90% of Robertsonian translocations, and the most frequently observed are the 13;14 and the 14;21 translocations (4). Most translocations between heterologs are dicentric and devoid of Ag-positive NOR (4)(5)(6)(7)(8).…”

mentioning

confidence: 99%

Structural basis for Robertsonian translocations in man: association of ribosomal genes in the nucleolar fibrillar center in meiotic spermatocytes and oocytes.

Stahl¹,

Luciani²,

Hartung³

et al. 1983

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

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The spatial relationships of acrocentric chromosomes were studied during prophase I of meiosis in human oocytes and spermatocytes by using cytogenetic techniques, electron microscopy, and in situ hybridization. Ultrastructural investigations revealed an ordered arrangement of nucleolar bivalents at the zygotene and pachytene stages. The end of the bivalent corresponding to the cytological satellite was consistently attached to the nuclear envelope. The fibrillar center of the nucleolus always contained rDNA chromatin fibers emanating from the secondary constriction region. Association of ribosomal genes from two bivalents in the same fibrillar center was frequently observed. Ultrastructural studies demonstrated the close proximity of chromatids in the short arm region of the involved nonhomologous acrocentrics. A breakage/reunion model based on our data can explain the formation of all observed types of Robertsonian translocations: monocentrics and dicentrics with or without rDNA.Robertsonian translocations are the most frequent form of chromosome rearrangement in man, their incidence being about 1% in the general population. They result from different modes of exchange occurring within the centromeric region of two acrocentric chromosomes, thus producing a metacentric or submetacentric element (1). In man, the chromosomal segment above the centromere is divided into three parts: the proximal short arm, the secondary constriction or stalk, which is the nucleolus organizer region (NOR), and the distal cytological satellite. The five pairs of acrocentric chromosomes share multiple copies of rRNA genes variably dispersed among the NORs (2, 3). Nonhomologous chromosomes are involved in 90% of Robertsonian translocations, and the most frequently observed are the 13;14 and the 14;21 translocations (4). Most translocations between heterologs are dicentric and devoid of Ag-positive NOR (4-8).The formation of Robertsonian translocations has been ascribed to chromatid exchange after a break between acrocentric chromosomes associated with the same nucleolus, during spermatogonial and oogonial mitosis (9). It has also been suggested that Robertsonian rearrangements result from an orderly, nonrandom process during meiotic pairing and exchange (10). Indeed, nonhomologous acrocentric chromosomes are often associated with the same nucleolus at meiotic prophase I in human spermatocytes and oocytes (11)(12)(13)(14). The nonrandom involvement of chromosomes in translocations can also be explained by an accidental meiotic recombination between partially homologous sites on nonhomologs. If the pairing is "end-to-end," crossing-over results in two recombinants, one acentric and the other dicentric (15). The two centromeres are so close to one another that they may act as a single centromere (16).Electron microscope studies provide more precise information about the relationship between the nucleolus and the acrocentric chromosomes. A connecting region of the nucleolus was reported in close association with the nucleolar chro...

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The fate of DNA statellites I, II, III and ribosomal DNA in a familial dicentric chromosome 13:14

Cited by 30 publications

References 28 publications

Pachytene analysis of a man with a 13q;14q translocation and infertility

Pachytene analysis of a man with a 13q;14q translocation and infertility

Homologous subfamilies of human alphoid repetitive DNA on different nucleolus organizing chromosomes.

Structural basis for Robertsonian translocations in man: association of ribosomal genes in the nucleolar fibrillar center in meiotic spermatocytes and oocytes.

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