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Casas-Delucchi CS, Brero A, Rahn HP, Solovei I, Wutz A, Cremer T, Leonhardt H, Cardoso MC. Histone acetylation controls the inactive X chromosome replication dynamics. Nat Commun 2011; 2:222. [PMID: 21364561 PMCID: PMC3072080 DOI: 10.1038/ncomms1218] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 01/27/2011] [Indexed: 12/20/2022] Open
Abstract
In mammals, dosage compensation between male and female cells is achieved by inactivating one female X chromosome (Xi). Late replication of Xi was proposed to be involved in the maintenance of its silenced state. Here, we show a highly synchronous replication of the Xi within 1 to 2 h during early-mid S-phase by following DNA replication in living mammalian cells with green fluorescent protein-tagged replication proteins. The Xi was replicated before or concomitant with perinuclear or perinucleolar facultative heterochromatin and before constitutive heterochromatin. Ectopic expression of the X-inactive-specific transcript (Xist) gene from an autosome imposed the same synchronous replication pattern. We used mutations and chemical inhibition affecting different epigenetic marks as well as inducible Xist expression and we demonstrate that histone hypoacetylation has a key role in controlling Xi replication. The epigenetically controlled, highly coordinated replication of the Xi is reminiscent of embryonic genome replication in flies and frogs before genome activation and might be a common feature of transcriptionally silent chromatin.
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Sato K, Torimoto Y, Hosoki T, Ikuta K, Takahashi H, Yamamoto M, Ito S, Okamura N, Ichiki K, Tanaka H, Shindo M, Hirai K, Mizukami Y, Otake T, Fujiya M, Sasaki K, Kohgo Y. Loss of ABCB7 gene: pathogenesis of mitochondrial iron accumulation in erythroblasts in refractory anemia with ringed sideroblast with isodicentric (X)(q13). Int J Hematol 2011; 93:311-318. [PMID: 21380928 DOI: 10.1007/s12185-011-0786-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 02/08/2011] [Accepted: 02/09/2011] [Indexed: 11/28/2022]
Abstract
An isodicentric (X)(q13) (idicXq13) is a rare, acquired chromosomal abnormality originated by deletion of the long arm from Xq13 (Xq13-qter), and is found in female patients with hematological disorders involving increased ringed sideroblasts (RSs), which are characterized by mitochondrial iron accumulation around the erythroblast nucleus. The cause of increased RSs in idicXq13 patients is not fully understood. Here, we report the case of a 66-year-old female presenting with refractory anemia with ringed sideroblasts (RARS), and idicXq13 on G-banded analysis. We identify the loss of the ABCB7 (ATP-binding cassette subfamily B member-7) gene, which is located on Xq13 and is involved in mitochondrial iron transport to the cytosol, by fluorescent in situ hybridization (FISH) analysis and the decreased expression level of ABCB7 mRNA in the patient's bone marrow cells. Further FISH analyses showed that the ABCB7 gene is lost only on the active X-chromosome, not on the inactive one. We suggest that loss of ABCB7 due to deletion of Xq13-qter at idicXq13 formation may have contributed to the increased RSs in this patient. These findings suggest that loss of the ABCB7 gene may be a pathogenetic factor underlying mitochondrial iron accumulation in RARS patients with idicXq13.
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Affiliation(s)
- Kazuya Sato
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan.
| | - Yoshihiro Torimoto
- Oncology Center, Asahikawa Medical University Hospital, Asahikawa, Hokkaido, Japan
| | - Takaaki Hosoki
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Katsuya Ikuta
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Hiroyuki Takahashi
- Department of Medical Laboratory and Blood Center, Asahikawa Medical University Hospital, Asahikawa, Hokkaido, Japan
| | - Masayo Yamamoto
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Satoshi Ito
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Naoka Okamura
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Kazuhiko Ichiki
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Hiroki Tanaka
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Motohiro Shindo
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | | | - Yusuke Mizukami
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Takaaki Otake
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Mikihiro Fujiya
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Kastunori Sasaki
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
| | - Yutaka Kohgo
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Midorigaoka-Higashi 2 jo 1 chome 1-1, Asahikawa, Hokkaido, 078-8510, Japan
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Dubey DD, Raman R. Mammalian sex chromosomes. IV. Replication heterogeneity in the late replicating facultative- and constitutive-heterochromatic regions in the X chromosomes of the mole rats, Bandicota bengalensis and Nesokia indica. Hereditas 2008; 115:275-82. [PMID: 1816171 DOI: 10.1111/j.1601-5223.1992.tb00570.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The karyotypes of Nesokia indica and Bandicota bengalensis are identical except for their sex chromosomes, which are much larger in Nesokia due to additional constitutive heterochromatin (C.H.). Replication patterns of their sex chromosomes were studied employing 3H-Tdr autoradiography and BrdUrd-FPG staining techniques. Though the "conservative" part of both early- and late-replicating X chromosomes revealed identical replication patterns in most cells, deviant patterns of only the late replicating X chromosome were encountered in approximately 10% cells. Surprisingly, these late-X variants were similar in the two species. The sex chromosome-associated C.H. segments replicated late in S-phase and, in females, the homologous heterochromatin replicated asynchronously--the later replicating one was predominantly associated with the late X. These results suggest structural and functional conservation of the X chromosomes as well as the possible influence of facultative heterochromatin (F.H.) on the replication of associated C.H. in these two species.
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Affiliation(s)
- D D Dubey
- Department of Zoology, Banaras Hindu University, Varanasi, India
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Lin MS, Wilson MG. The sequence of DNA replication in an iso-dicentric X-chromosome in peripheral blood lymphocytes and skin fibroblasts from the same individual. Hum Genet 1983; 65:139-43. [PMID: 6654328 DOI: 10.1007/bf00286650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A comparison of the sequence of DNA replication in an isodicentric (idic) X chromosome was made between peripheral blood lymphocytes and skin fibroblasts from a 33-year-old female with primary amenorrhea, somatic stigmata of Turner syndrome, and normal stature and intelligence. The patient had a karyotype 45,X/46,X,idic(X)(q27.1) to lymphocytes and 46,X,idic(X)(q27.1) in skin fibroblasts. Both centromeric regions of the idic X showed C-staining but only one primary constriction. BrdU-33258 Hoechst-Giemsa techniques were used to analyze regional DNA replication patterns. The idic X chromosome was always late replicating in lymphocytes and skin fibroblasts, except that about 1-2% of cells completed replication simultaneously in both normal and idic X chromosomes. Fifty-six percent of the asymmetric patterns in lymphocytes showed an equal proportion of early and late functional and non-functional centromere halves. In skin fibroblasts, 60.8% of cells were asymmetric: the functional half tended to replicate later than the non-functional half. Some differences were observed between these two cell types. As examples, band q23 was late replicating in lymphocytes, but early replicating in fibroblasts; q25 was intermediate to late replicating in lymphocytes, but one of the last bands to complete replication in fibroblasts. Thus, different cell typed influenced the replication kinetics of the idic(X). Furthermore, several variants of the replication sequence were found in both cell types. The findings support the hypothesis that the control of DNA replication in the inactive X chromosome is multifocal, and suggest that the active idic X chromosome replication may reflect a relative lack of self-control or heterogeneity of cell population.
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Yu CW, Chen H, Fowler M. Specific terminal DNA replication sequence of X chromosomes in different tissues of a live-born triploid infant. AMERICAN JOURNAL OF MEDICAL GENETICS 1983; 14:501-11. [PMID: 6683074 DOI: 10.1002/ajmg.1320140314] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Using the thymidine pulse method, DNA replication kinetics were studied on cells derived from cartilage, gonad, lymphocytes, and skin of a live-born triploid (69,XXY) infant with typical clinical findings. Replication studies showed that 3% of the lymphocytes had one early and one late replicating X, and 97% of the lymphocytes, and cartilage, gonad, and skin cells had two early replicating X's. Asynchronous DNA replication between the two early replicating X's was observed in all tissues (range 25-40%). The predominant terminal replication sequence of X chromosomes from chondrocytes, gonad, and skin fibroblast differed from that of the lymphocytes. Thus, a tissue-specific DNA replication pattern of the early-replicating X chromosome may be present. In every tissue, the last band to complete DNA replication was Xq21. Polymorphisms of metaphase chromosomes of parents and the patient were studied by Q-banding. The possible origin of the extra haploid set of chromosomes is discussed.
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Yu CW, Priest JH, Byrd JR. DNA replication sequence in a dicentric (functionally monocentric) X chromosome formed by the joining of two X chromosomes at region p22. AMERICAN JOURNAL OF MEDICAL GENETICS 1982; 11:305-17. [PMID: 7081296 DOI: 10.1002/ajmg.1320110307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In this study we used densitometry to evaluate DNA replication kinetics in a rearranged chromosome formed by the joining of two X chromosomes at region p22. No 45X mosaicism is present in peripheral blood or fibroblast cultures. The patient has primary amenorrhea, short stature, and gonadal dysgenesis. The sequence of replication in the majority of cells is p11, q11, q13, q22-24, q12, p22, q26, q28, q27, q25, and p21, q21. Thus p11 is the earliest region to replicate, and q21 is the last. In 66% of 127 cells analyzed, the replication pattern is asymmetric, and bands q12, q26, and q28 are most likely to be out of phase on the two sides of the breakpoint. We find that band p22 has a delay of replication compared to an abnormal X derived from two X chromosomes joined at the q23 region previously reported by us. Structural rearrangement may therefore delay replication in the region of the break.
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