Centromere Protein B
Chromosomal Proteins, Non-Histone
In Situ Hybridization, Fluorescence
Chromosomes, Artificial, Human
Aurora Kinase B
Schizosaccharomyces pombe Proteins
Cell Cycle Proteins
Molecular Sequence Data
Saccharomyces cerevisiae Proteins
Meiotic Prophase I
Repetitive Sequences, Nucleic Acid
Crossing Over, Genetic
Sister Chromatid Exchange
Chromosomes, Artificial, Bacterial
Chromosomes, Artificial, Mammalian
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
Amino Acid Sequence
Chromatin Assembly and Disassembly
Physical Chromosome Mapping
All 16 centromere DNAs from Saccharomyces cerevisiae show DNA curvature. (1/2290)All 16 centromere DNA regions of Saccharomyces cerevisiae including 90 bp framing sequences on either side were cloned. These 300 bp long centromere regions were analysed by native polyacrylamide gel electrophoresis and found to display a reduced mobility indicative of DNA curvature. The degree of curvature is centromere dependent. The experimental data were confirmed by computer analysis of the 3-dimensional structure of the CEN DNAs. Altogether these data provide further evidence for a model for budding yeast centromeres in which CEN DNA structure could be important for the assembly, activity and/or regulation of the centromere protein-DNA complex. (+info)
Localization and properties of a silencing element near the mat3-M mating-type cassette of Schizosaccharomyces pombe. (2/2290)Transcription is repressed in a segment of Schizosaccharomyces pombe chromosome II that encompasses the mat2-P and mat3-M mating-type cassettes. Chromosomal deletion analysis revealed the presence of a repressor element within 500 bp of mat3-M. This element acted in synergy with the trans-acting factors Swi6, Clr1, Clr2, Clr3, and Clr4 and had several properties characteristic of silencers: it did not display promoter specificity, being able to silence not only the M mating-type genes but also the S. pombe ura4 and ade6 genes placed on the centromere-distal side of the mat3-M cassette; it could repress a gene when placed further than 2.6 kb from the promoter and it acted in both orientations, although with different efficiencies, the natural orientation repressing more stringently than the reverse. Following deletion of this element, two semistable states of expression of the mat3-M region were observed and these two states could interconvert. The deletion did not affect gene expression in the vicinity of the mat2-P cassette, 11 kb away from mat3-M. Conversely, deleting 1.5 kb on the centromere-proximal side of the mat2-P cassette, which was previously shown to partially derepress transcription around mat2-P, had no effect on gene expression near mat3-M. A double deletion removing the mat2-P and mat3-M repressor elements had the same effect as the single deletions on their respective cassettes when assayed in cells of the M mating type. These observations allow us to refine a model proposing that redundant pathways silence the mating type region of S. pombe. (+info)
A new X linked neurodegenerative syndrome with mental retardation, blindness, convulsions, spasticity, mild hypomyelination, and early death maps to the pericentromeric region. (3/2290)We report on a family with an X linked neurodegenerative disorder consisting of mental retardation, blindness, convulsions, spasticity, and early death. Neuropathological examination showed mild hypomyelination. By linkage analysis, the underlying genetic defect could be assigned to the pericentromeric region of the X chromosome with a maximum lod score of 3.30 at theta=0.0 for the DXS1204 locus with DXS337 and PGK1P1 as flanking markers. (+info)
Short DNA fragments without sequence similarity are initiation sites for replication in the chromosome of the yeast Yarrowia lipolytica. (4/2290)We have previously shown that both a centromere (CEN) and a replication origin are necessary for plasmid maintenance in the yeast Yarrowia lipolytica (). Because of this requirement, only a small number of centromere-proximal replication origins have been isolated from Yarrowia. We used a CEN-based plasmid to obtain noncentromeric origins, and several new fragments, some unique and some repetitive sequences, were isolated. Some of them were analyzed by two-dimensional gel electrophoresis and correspond to actual sites of initiation (ORI) on the chromosome. We observed that a 125-bp fragment is sufficient for a functional ORI on plasmid, and that chromosomal origins moved to ectopic sites on the chromosome continue to act as initiation sites. These Yarrowia origins share an 8-bp motif, which is not essential for origin function on plasmids. The Yarrowia origins do not display any obvious common structural features, like bent DNA or DNA unwinding elements, generally present at or near eukaryotic replication origins. Y. lipolytica origins thus share features of those in the unicellular Saccharomyces cerevisiae and in multicellular eukaryotes: they are discrete and short genetic elements without sequence similarity. (+info)
Analysis of the 10q23 chromosomal region and the PTEN gene in human sporadic breast carcinoma. (5/2290)We examined a panel of sporadic breast carcinomas for loss of heterozygosity (LOH) in a 10-cM interval on chromosome 10 known to encompass the PTEN gene. We detected allele loss in 27 of 70 breast tumour DNAs. Fifteen of these showed loss limited to a subregion of the area studied. The most commonly deleted region was flanked by D10S215 and D10S541 and encompasses the PTEN locus. We used a combination of denaturing gradient gel electrophoresis and single-strand conformation polymorphism analyses to investigate the presence of PTEN mutations in tumours with LOH in this region. We did not detect mutations of PTEN in any of these tumours. Our data show that, in sporadic breast carcinoma, loss of heterozygosity of the PTEN locus is frequent, but mutation of PTEN is not. These results are consistent with loss of another unidentified tumour suppressor in this region in sporadic breast carcinoma. (+info)
Specific destruction of kinetochore protein CENP-C and disruption of cell division by herpes simplex virus immediate-early protein Vmw110. (6/2290)Examination of cells at the early stages of herpes simplex virus type 1 infection revealed that the viral immediate-early protein Vmw110 (also known as ICP0) formed discrete punctate accumulations associated with centromeres in both mitotic and interphase cells. The RING finger domain of Vmw110 (but not the C-terminal region) was essential for its localization at centromeres, thus distinguishing the Vmw110 sequences required for centromere association from those required for its localization at other discrete nuclear structures known as ND10, promyelocytic leukaemia (PML) bodies or PODs. We have shown recently that Vmw110 can induce the proteasome-dependent loss of several cellular proteins, including a number of probable SUMO-1-conjugated isoforms of PML, and this results in the disruption of ND10. In this study, we found some striking similarities between the interactions of Vmw110 with ND10 and centromeres. Specifically, centromeric protein CENP-C was lost from centromeres during virus infection in a Vmw110- and proteasome-dependent manner, causing substantial ultrastructural changes in the kinetochore. In consequence, dividing cells either became stalled in mitosis or underwent an unusual cytokinesis resulting in daughter cells with many micronuclei. These results emphasize the importance of CENP-C for mitotic progression and suggest that Vmw110 may be interfering with biochemical mechanisms which are relevant to both centromeres and ND10. (+info)
Dynamic repositioning of genes in the nucleus of lymphocytes preparing for cell division. (7/2290)We show that several transcriptionally inactive genes localize to centromeric heterochromatin in the nucleus of cycling but not quiescent (noncycling) primary B lymphocytes. In quiescent cells, centromeric repositioning of inactive loci was induced after mitogenic stimulation. A dynamic repositioning of selected genes was also observed in developing T cells. Rag and TdT loci were shown to relocate to centromeric domains following heritable gene silencing in primary CD4+8+ thymocytes, but not in a phenotypically similar cell line in which silencing occurred but was not heritable. Collectively, these data indicate that the spatial organization of genes in cycling and noncycling lymphocytes is different and that locus repositioning may be a feature of heritable gene silencing. (+info)
Probing the Saccharomyces cerevisiae centromeric DNA (CEN DNA)-binding factor 3 (CBF3) kinetochore complex by using atomic force microscopy. (8/2290)Yeast centromeric DNA (CEN DNA) binding factor 3 (CBF3) is a multisubunit protein complex that binds to the essential CDEIII element in CEN DNA. The four CBF3 proteins are required for accurate chromosome segregation and are considered to be core components of the yeast kinetochore. We have examined the structure of the CBF3-CEN DNA complex by atomic force microscopy. Assembly of CBF3-CEN DNA complexes was performed by combining purified CBF3 proteins with a DNA fragment that includes the CEN region from yeast chromosome III. Atomic force microscopy images showed DNA molecules with attached globular bodies. The contour length of the DNA containing the complex is approximately 9% shorter than the DNA alone, suggesting some winding of DNA within the complex. The measured location of the single binding site indicates that the complex is located asymmetrically to the right of CDEIII extending away from CDEI and CDEII, which is consistent with previous data. The CEN DNA is bent approximately 55 degrees at the site of complex formation. A significant fraction of the complexes are linked in pairs, showing three to four DNA arms, with molecular volumes approximately three times the mean volumes of two-armed complexes. These multi-armed complexes indicate that CBF3 can bind two DNA molecules together in vitro and, thus, may be involved in holding together chromatid pairs during mitosis. (+info)
There are several types of genetic nondisjunction, including:
1. Robertsonian translocation: This type of nondisjunction involves the exchange of genetic material between two chromosomes, resulting in a mixture of genetic information that can lead to developmental abnormalities.
2. Turner syndrome: This is a rare condition that occurs when one X chromosome is missing or partially present, leading to physical and developmental abnormalities in females.
3. Klinefelter syndrome: This condition occurs when an extra X chromosome is present, leading to physical and developmental abnormalities in males.
4. Trisomy 13: This condition occurs when there are three copies of chromosome 13, leading to severe developmental and physical abnormalities.
5. Trisomy 18: This condition occurs when there are three copies of chromosome 18, leading to severe developmental and physical abnormalities.
Genetic nondisjunction can be caused by various factors, including genetic mutations, errors during meiosis, or exposure to certain chemicals or radiation. It can be diagnosed through cytogenetic analysis, which involves studying the chromosomes of cells to identify any abnormalities.
Treatment for genetic nondisjunction depends on the specific type and severity of the condition. In some cases, no treatment is necessary, while in others, medication or surgery may be recommended. Prenatal testing can also be done to detect genetic nondisjunction before birth.
In summary, genetic nondisjunction is a chromosomal abnormality that occurs during meiosis and can lead to developmental and physical abnormalities. It can be caused by various factors and diagnosed through cytogenetic analysis. Treatment depends on the specific type and severity of the condition, and prenatal testing is available to detect genetic nondisjunction before birth.
Definition: Isochromosomes are chromosomes that have the same banding pattern and the same number of genes, but differ in size due to variations in the amount of repetitive DNA sequences.
Example: In some cases of cancer, isochromosomes may be present as a result of a chromosomal abnormality. These abnormalities can lead to changes in the expression of genes and potentially contribute to the development and progression of cancer.
Synonyms: Isochromosomes are also known as isochromosomi or isochromosomal aberrations.
Antonyms: There are no direct antonyms for isochromosomes, but related terms that refer to abnormalities in chromosome structure or number include aneuploidy, translocations, and deletions.
1. Genetics Home Reference (2022). Crest syndrome. Retrieved from
2. Orphanet (2022). Crest syndrome. Retrieved from
3. MedlinePlus (2022). Crest syndrome. Retrieved from
There are several types of aneuploidy, including:
1. Trisomy: This is the presence of an extra copy of a chromosome. For example, Down syndrome is caused by an extra copy of chromosome 21 (trisomy 21).
2. Monosomy: This is the absence of a chromosome.
3. Mosaicism: This is the presence of both normal and abnormal cells in the body.
4. Uniparental disomy: This is the presence of two copies of a chromosome from one parent, rather than one copy each from both parents.
Aneuploidy can occur due to various factors such as errors during cell division, exposure to certain chemicals or radiation, or inheritance of an abnormal number of chromosomes from one's parents. The risk of aneuploidy increases with age, especially for women over the age of 35, as their eggs are more prone to errors during meiosis (the process by which egg cells are produced).
Aneuploidy can be diagnosed through various methods such as karyotyping (examining chromosomes under a microscope), fluorescence in situ hybridization (FISH) or quantitative PCR. Treatment for aneuploidy depends on the underlying cause and the specific health problems it has caused. In some cases, treatment may involve managing symptoms, while in others, it may involve correcting the genetic abnormality itself.
In summary, aneuploidy is a condition where there is an abnormal number of chromosomes present in a cell, which can lead to various developmental and health problems. It can occur due to various factors and can be diagnosed through different methods. Treatment depends on the underlying cause and the specific health problems it has caused.
Causes of Chromosomal Instability:
1. Genetic mutations: Mutations in genes that regulate the cell cycle or chromosome segregation can lead to CIN.
2. Environmental factors: Exposure to certain environmental agents such as radiation and certain chemicals can increase the risk of developing CIN.
3. Errors during DNA replication: Mistakes during DNA replication can also lead to CIN.
Types of Chromosomal Instability:
1. Aneuploidy: Cells with an abnormal number of chromosomes, either more or fewer than the normal diploid number (46 in humans).
2. Structural changes: Deletions, duplications, inversions, translocations, and other structural changes can occur in the chromosomes.
3. Unstable chromosome structures: Chromosomes with abnormal shapes or structures, such as telomere shortening, centromere instability, or chromosome breaks, can also lead to CIN.
Effects of Chromosomal Instability:
1. Cancer: CIN can increase the risk of developing cancer by disrupting normal cellular processes and leading to genetic mutations.
2. Aging: CIN can contribute to aging by shortening telomeres, which are the protective caps at the ends of chromosomes that help maintain their stability.
3. Neurodegenerative diseases: CIN has been implicated in the development of certain neurodegenerative diseases such as Alzheimer's and Parkinson's.
4. Infertility: CIN can lead to infertility by disrupting normal meiotic recombination and chromosome segregation during gametogenesis.
Detection and Diagnosis of Chromosomal Instability:
1. Karyotyping: This is a technique used to visualize the entire set of chromosomes in a cell. It can help identify structural abnormalities such as deletions, duplications, or translocations.
2. Fluorescence in situ hybridization (FISH): This technique uses fluorescent probes to detect specific DNA sequences or proteins on chromosomes. It can help identify changes in chromosome structure or number.
3. Array comparative genomic hybridization (aCGH): This technique compares the genetic material of a sample to a reference genome to identify copy number changes.
4. Next-generation sequencing (NGS): This technique can identify point mutations and other genetic changes in DNA.
Treatment and Management of Chromosomal Instability:
1. Cancer treatment: Depending on the type and stage of cancer, treatments such as chemotherapy, radiation therapy, or surgery may be used to eliminate cancer cells with CIN.
2. Prenatal testing: Pregnant women with a family history of CIN can undergo prenatal testing to detect chromosomal abnormalities in their fetuses.
3. Genetic counseling: Individuals with a family history of CIN can consult with a genetic counselor to discuss risk factors and potential testing options.
4. Lifestyle modifications: Making healthy lifestyle choices such as maintaining a balanced diet, exercising regularly, and not smoking can help reduce the risk of developing cancer and other diseases associated with CIN.
In conclusion, chromosomal instability is a common feature of many human diseases, including cancer, and can be caused by a variety of factors. The diagnosis and management of CIN require a multidisciplinary approach that includes cytogenetic analysis, molecular diagnostics, and clinical evaluation. Understanding the causes and consequences of CIN is crucial for developing effective therapies and improving patient outcomes.
Centromere protein E
Centromere protein B
Repeated sequence (DNA)
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- However, up to the middle 1990s, scientists did not know the DNA sequences or chromatin structure of centromeres in higher eukaryotes. (edu.sa)
- Kinetochores become established on a part of the centromere (specialized chromatin), with the presence of CENP-A (a variant of histone H3) as a major hallmark [ 8 ]. (springeropen.com)
- Srr1/Ber1 containing the SRR1-like domain and Skb1 the human protein arginine methyltransferase 5 (PRMT5) homolog cause gross chromosomal rearrangements at centromeres in the absence of Rad51 recombinase. (nature.com)
- The functional role of the centromere as the chromosomal attachment site for spindle fibers was recognized more than a century ago. (edu.sa)
- To guarantee faithful chromosomal segregation, there must be a proper assembling of the kinetochore (a protein complex with multiple subunits) at the centromere during the process of cell division. (springeropen.com)
- Functional Identification of the Plasmodium Centromere and Generation of a Plasmodium Artificial Chromosome. (ox.ac.uk)
- A chromatid is one-half of a replicated chromosome, being considered as a chromatid when attached at the centromere and prior to separation and becoming a daughter chromosome. (newworldencyclopedia.org)
- Sister chromatids are attached at an area called the centromere (not necessarily at the center of the chromosome). (newworldencyclopedia.org)
- Chromosome analysis demonstrated significantly increased centromere fragmentation and translocations from each MWCNT at each dose. (cdc.gov)
- Given an estimated length of 6.7µm for chromosome 1P and the mean percentage above, this BAC is approximately 5.6µm±0.1µm from the chromosome centromere. (cornell.edu)
- The inner kinetochore on the other hand serves as a host for the CCAN (constitutive centromere-associated network), a complex consisting of sixteen different centromeric proteins (CENPs) [ 12 ], most of which were identified originally in the vertebrates' CENP-A interactome [ 13 ]. (springeropen.com)
- The centromeres of many eukaryotes consist partly of large arrays of short tandem repeats, though the actual sequence of the repeat varies widely across taxa. (haldanessieve.org)
- As an ancient tetraploid maize originally had 20 chromosomes with 20 centromeres. (haldanessieve.org)
- During the anaphase, the chromosomes divide at the centromere and start moving towards opposite poles. (syvum.com)
- The chromosomes are arranged in pairs, and aligned using the position of each chromosome's centromere. (cdc.gov)
- In 1996, plant scientists discovered several repetitive DNA elements that are conserved in the centromeres of distantly related plant species, which opened the door for plant centromere research. (edu.sa)
- Centromeres have the potential to play a central role in speciation, yet our ability to study them has been limited because of their repetitive nature. (haldanessieve.org)
- It is located around the centromere and usually contains repetitive sequences. (newworldencyclopedia.org)
- This guest post is by Paul Bilinski on his paper with coauthors Diversity and evolution of centromere repeats in the maize genome BioRxived here . (haldanessieve.org)
- The establishment and maintenance of centromeres is not defined by the underlying DNA sequences. (edu.sa)
- The Gordon Research Seminar on Centromere Biology is a unique forum for graduate students, post-docs, and other scientists with comparable levels of experience and education to present and exchange new data and cutting edge ideas. (grc.org)
- This GRS will be held in conjunction with the "Centromere Biology" Gordon Research Conference (GRC). (grc.org)
- Centromere biology: what have we learned from plants? (edu.sa)
- Several plant species have provided excellent models to dissect the genetic and epigenetic changes that may play a role in centromere function and evolution. (edu.sa)
- We hope our insights into centromere repeat evolution will build toward a better understanding of their role in evolution. (haldanessieve.org)
- Using positional and genetic relatedness information from the fully-sequenced centromeres 2 and 5, we found high within-cluster similarity, suggesting that tandem duplications drove most CentC copy number increase. (haldanessieve.org)
- Topics will span a variety of organisms and will include changes in centromere function and composition across the cell division cycle, and highlight emerging methods and areas of interest in the field. (grc.org)
- Finally, we demonstrated that CNF induced predominately centromere-positive MN in primary human small airway epithelial cells (SAEC) indicating aneugenic events. (cdc.gov)
- Molecular basis of CENP-C association with the CENP-A nucleosome at yeast centromeres. (nih.gov)
- Meiotic drive of selfish centromeres, or centromere drive, can explain the "centromere paradox": rapid evolution of both centromere DNA sequences and genes encoding centromere-binding proteins despite conserved centromere function in segregation. (nih.gov)
- Selfish centromeres exploit the same destabilizing activity, by selectively promoting re-orientation to bias their segregation to the egg (Fig. 2C). (nih.gov)
- Although regulation of centromeric function by epigenetic factors has been well-studied, the contributions of the underlying DNA sequences have been much less well defined, and existing methodologies for studying centromere genomics in biology are laborious. (nih.gov)
- Thus, centromere DNA and centromere proteins continually evolve in conflict with each other, analogous to a molecular arms race between viruses and the immune system. (nih.gov)
- Rapid molecular assays to study human centromere genomics. (nih.gov)
- This theory has been influential, but it was largely unknown how centromere drive happens cell biologically. (nih.gov)
- The centromere drive theory is based on the idea that natural selection favors centromere DNA sequences that act selfishly in female meiosis. (nih.gov)
- Fitness costs associated with centromere drive would also select for alleles of centromere-binding proteins that suppress centromere drive. (nih.gov)
- The lab has established the first experimental system for centromere drive in mice, leading to three major advances. (nih.gov)
- Centromere drive and the resulting conflicts between centromere DNA and centromere proteins can generate distinct evolutionary trajectories in different populations, explaining the large divergence in centromere DNA even between closely-related species or strains. (nih.gov)
- First, we showed that centromeres with expanded satellite repeats act selfishly to preferentially orient towards the egg pole of the meiotic spindle to remain in the egg (Fig. 1 and 2A). (nih.gov)