The sex chromosomes of the Chinese hamster: constitutive heterochromatin deficient in repetitive DNA sequences

Arrighi, Francis E.; Hsu, T. C.; Pathak, Subodh Kumar; Sawada, Hiroyoshi

doi:10.1159/000130278

Cited by 73 publications

(17 citation statements)

References 7 publications

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“…According to the usual criteria, it would be reasonable to think that such regions are made of constitutive heterochromatin, since they are late replicating as shown by BrdU incor poration and since they are stained by the convention al C-banding technique. However, Arrighi et al (1974) failed to detect highly repetitive DNA se quences in the heterochromatic regions which can explain their lower resistance to alkali treatment. Moreover our observation of the lack of affinity of these regions for Giemsa 11, believed to stain satellite DNA, is consistent with the fact that no synthesis of satellite DNA has been observed during meiotic re combination (Hotta and Stern, 1978).…”

Section: Discussionmentioning

confidence: 98%

Heterochromatin heterogeneity in Chinese hamster sex bivalents

Murer‐Orlando¹,

Richer²

1983

Cytogenet Genome Res

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The heterochromatin of the Chinese hamster sex chromosomes was analyzed by different banding techniques. Combined results obtained after differential Ba(OH)₂ treatment, BrdU incorporation, Giemsa 11, and staining with quinacrine permitted the characterization of different regions in the heterochromatic portions of the X and Y chromosomes. In the light of these observations, the chiasma observed in the sex bivalent of Chinese hamster spermatocytes was localized within specific heterochromatic regions. The homologous segments consist of the entire short arm of the Y and the distal end of the long arm of the X up to band q21. These regions are probably not rich in highly repetitive DNA sequences, which are more resistant to alkali denaturation, or in satellite DNA, which is stained by Giemsa 11. Thus the heterochromatin in the homologous regions of the sex chromosomes allows the formation of a chiasma. The heterogeneity found in these heterochromatic regions may help to establish a more precise relationship between heterochromatin and recombination.

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Section: Discussionmentioning

confidence: 98%

Heterochromatin heterogeneity in Chinese hamster sex bivalents

Murer‐Orlando¹,

Richer²

1983

Cytogenet Genome Res

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“…One hour after the addition of colcemid, the samples were harvested and spread for autoradiography. Each sample was scored for the percentage of mitotic figures labeled (-o-o-o-o-) and for the percentage of It is somewhat surprising that the HSR in both lines begins replication in early S since both HSRs C-band (Biedler and Spengler, 1976), and C-banding have been correlated with late replication (Arrighi et al, 1974). The early replication of the HSRs could be fit into a model suggested by Prescott (1970) in which most replicons (excluding characteristie latereplicating ones) begin replication in early S, but some take longer than others to complete.…”

Section: Discussionmentioning

confidence: 99%

Replication pattern of a large homogenously staining chromosome region in antifolate‐resistant Chinese hamster cell lines

Hamlin¹,

Biedler²

1981

Journal Cellular Physiology

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We have investigated the replication pattern of a large, homogenously staining chromosome region (HSR) in two antifolate-resistant Chinese hamster cell lines. This region is believed to be the location of an amplified genetic sequence which includes at least the gene coding for dihydrofolate reductase and which may be present in as many as 200 copies. It is shown that the HSR in both cell lines is among the first chromosome regions to begin DNA synthesis after reversal of an early G1 block. In cells synchronized in the S period with hydroxyurea, it is also clear that the HSR in both cell lines begins replication at many sites within its length in early S. The replicons comprising the HSR therefore may respond to a common initiation signal in early S. In on cell line (A3), replication of the HSR requires, at most, 3 hours of a 7-hour S period; in a second line (MQ19), replication proceeds for approximately 5 hours. In neither line does replication of the HSR occur concomitantly with synthesis of characteristic late replicating regions. These results were confirmed in exponential cultures using a retroactive labeling technique. The significance of these findings is discussed with reference to the possible origin and arrangement of the amplified sequence in these two cell lines.

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“…Heterochromatin regions are not uniform in structure (Cortes and Escalza, 1986). C-bands are usually regarded as the sites of highly repetitive DNAs, but not all C-bands contain highly repetitive DNAs (Arrighi et al, 1974;Wheeler et al, 1978). The minor incompatibility of the late replication banding pattern with C-banding pattern reflects the structural diversity of C-bands, and indicates that the late replicating regions are not homogeneous.…”

Section: Discussionmentioning

confidence: 99%

Characterization of the late replication banding patterns in barley chromosomes.

1997

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Replicating DNA regions on barley chromosomes were investigated by a replication banding technique. Of all chromosomal regions, the late replicating regions, in which DNA replicated in the last third of S phase, were detected as exceptionally distinct bands. Each late replicating region had its own timing and duration to replicate, which were not influenced by any translocations. This suggested that the late replication was highly associated with the structure of its related chromosomal region. By using the series of translocated chromosome lines, the late replication banding patterns of seven barley chromosomes were identified. The late replication banding pattern was similar to the C-banding pattern. The relationships of the late replicating regions with heterochromatin and C-banding regions are also discussed.

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The sex chromosomes of the Chinese hamster: constitutive heterochromatin deficient in repetitive DNA sequences

Cited by 73 publications

References 7 publications

Heterochromatin heterogeneity in Chinese hamster sex bivalents

Heterochromatin heterogeneity in Chinese hamster sex bivalents

Replication pattern of a large homogenously staining chromosome region in antifolate‐resistant Chinese hamster cell lines

Characterization of the late replication banding patterns in barley chromosomes.

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