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Topic: Sister chromatid

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	2002 Science--Amersham Prize
		Sister chromatid segregation is dependent on sister chromatid cohesion, which is only established during replication and holds sisters together until anaphase.
		Sister chromatid cohesion plays a pivotal role during both divisions, by ensuring that chromosomes containing homolog centromeres segregate to opposite poles during meiosis I, and chromosomes containing sister centromeres segregate during meiosis II.
		First, sister kinetochore attachment to opposite poles is prevented during meiosis I. Second, sister chromatid cohesion distal to cross-overs holds homologs together, promoting attachment of homologs to opposite poles.
	www.sciencemag.org /feature/data/pharmacia/2002/toth.dtl (1102 words)

	Douglas E. Koshland
		Sister chromatids are not, however, passive substrates in this process but rather actively participate in their own segregation.
		Pairing is needed to establish a stable bipolar attachment of sister chromatids to microtubules emanating from opposite poles of the mitotic spindle.
		Sister chromatids also condense, which helps to resolve them into distinct domains, reducing their entanglement while they move during mitosis.
	www.hhmi.org /research/investigators/koshland.html (913 words)

	Interactive Fly, Drosophila
		Sister chromatids remain paired throughout the G2 phase and during the initial phase of mitosis (prophase) while chromatin is condensed and the spindle is assembled.
		Inhibitors of sister chromatid separation that are degraded during the metaphase-anaphase transition by the APC/C pathway, and that function to a variable extent as activators of sister chromatid separation, have been described previously in yeast and vertebrates.
		The timing of sister chromatid separation under normal conditions in budding yeast, when spindle or DNA damage checkpoints are not activated, is also not controlled by Pds1p degradation, because it occurs with normal kinetics in cells lacking Pds1p (Leismann, 2000).
	www.sdbonline.org /fly/newgene/pimples1.htm (3761 words)

	EMF-Portal - Elevated sister chromatid exchange frequencies in dividing human peripheral blood lymphocytes exposed to ...
		Elevated sister chromatid exchange frequencies in dividing human peripheral blood lymphocytes exposed to 50 Hz magnetic fields.
		Sister chromatid exchange frequencies were scored in dividing peripheral blood lymphocytes from six healthy male donors in two sets of experiments to determine reproducibility.
		A significant increase in the number of sister chromatid exchanges/cell in the grouped experimental conditions compared to the controls was found in both sets.
	www.emf-portal.org /viewer.php?l=e&aid=14327 (617 words)

	Paul Connor Megee, Ph.D. (Site not responding. Last check: 2007-10-20)
		The cohesion of replicated chromosomes or sister chromatids plays a fundamental role in chromosome organization and in the segregation of sister chromatids to daughter cells during mitosis.
		Sister chromatid cohesion occurs along the length of the chromosome and is especially robust in centromeric regions where it is thought to promote the bilateral attachment of sister kinetochores to microtubules emanating from opposite spindle poles.
		This arrangement ensures that sister chromatids are segregated to opposite poles of the cell during the ensuing mitosis.
	www.uchsc.edu /bsp/profiles/megeep.htm (495 words)

	Re: What is the mechanism of Sister Chromatid Exchange ?
		Sister Chromatid Exchange, or SCE, is the exchange of homologous stretches of DNA sequence between sister chromatids.
		Sister chromatids come in pairs, consisting of one original chromosome and its identical copy, generated during DNA replication.
		Sister chromatid exchange occurs during mitosis, when condensed sister chromatids pair up.
	www.madsci.org /posts/archives/aug2000/967264433.Ge.r.html (520 words)

	Sloan-Kettering - Projects: Partner Choice in Homologous Recombination: Sister Chromatid Repair, LOH, and Translocations
		We found that sister chromatids serve as repair templates at high frequency (Johnson et al.
		Sister chromatids, on the other hand, are in close proximity to each other.
		Since sister chromatids are identical to each other, recombination with a sister chromatid is expected, in most cases, to be a precise way for repairing DNA damage.
	www.mskcc.org /mskcc/html/10575.cfm (362 words)

	Mei-S332
		Sister chromatids are tightly apposed at their centromeric regions, but it is not known whether this is due to cohesion at the functional centromere or at flanking centric heterochromatin.
		Since the sister chromatids remain associated until late in the first division, chromosomes segregate normally during meiosis I, and the genetic consequences of premature sister-chromatid dissociation are seen as nondisjunction in meiosis II.
		Sister chromatid associations in mei-S332 are generally normal during prophase I and metaphare I. By telophase I, sister chromatids have frequently precociously separated in both mutants.
	www.sdbonline.org /fly/newgene/mei332-4.htm (2674 words)

	79.65 In vivo sister chromatid exchange assay.
		The in vivo sister chromatid exchange (SCE) assay detects the ability of a chemical to enhance the exchange of DNA between two sister chromatids of a duplicating chromosome.
		Sister chromatid exchange means a reciprocal interchange of the two chromatid arms within a single chromosome.
		This exchange is visualized during the metaphase portion of the cell cycle and presumably requires the enzymatic incision, translocation and ligation of at least two DNA helices.
	www.setonresourcecenter.com /cfr/40CFR/P79_044.HTM (1209 words)

	Cohesion
		Sister chromatid exchanges are routinely observed after exposure of cells to DNA damaging agents.
		Sister chromatids remain closely connected to one another through replication and chromatin condensation.
		The Drosophila melanogaster mei-5332 gene is required for sister chromatid cohesion in meiosis I. It localizes to centromeres through meiosis until anaphase II (ref).
	opbs.okstate.edu /~melcher/mg/MGW1/MG13611.html (458 words)

	Carnegie Institution
		Sister chromatids are not, however, passive substrates in this process but rather actively participate in their own segregation by virtue of three specific structural features.
		The third structural feature of sister chromatids is their condensation, which helps to minimize the entanglement of chromosomes while they move during mitosis.
		At the onset of anaphase, cohesion is dissolved and sister chromatid segregation ensues.
	www.ciwemb.edu /labs/koshland (950 words)

	A Manyfold Increase in Sister Chromatid Exchanges in Bloom's Syndrome Lymphocytes -- Chaganti et al. 71 (11): 4508 -- ...
		In the present experiments, a cytogenetic technique by which the sister chromatids of a metaphase chromosome are stained differentially has been used to demonstrate a striking and possibly specific, but hitherto unrecognized, increase in the frequency with which sister chromatids also exchange segments.
		Normal frequencies of sister chromatid exchanges were found in cells heterozygous for the Bloom's syndrome gene, and also in cells either homozygous or heterozygous for the genes of the Louis-Bar (ataxia telangiectasia) syndrome and Fanconi's anemia, two other rare disorders characterized by chromosome instability.
		In a differentially stained chromatid interchange configuration discovered during the study, it was possible to determine the new distribution of both sister and non-sister-but-homologous chromatids that had resulted from numerous exchanges.
	www.pnas.org /cgi/content/abstract/71/11/4508 (1498 words)

	Whitehead Institute - Glue-like Protein
		MEI-S332 is the glue that holds sister chromatids together between the first act of meiosis and the second.
		This is most evident at the beginning of the second act of meiosis, when the sister chromatid units should be lined up in an orderly row, waiting for the guide wires to pull them apart.
		The sister chromatid units are gone, replaced by a jumble of individual chromosomes.
	www.wi.mit.edu /news/archives/1995/tow_1020.html (1082 words)

	Micronucleus and Sister Chromatid Exchange Frequency in Endemic Fluorosis
		Here we use the technique of micronucleus (MN) and sister chromatid exchange (SCE) to detect mutagenicity and potential carcinogenicity from fluoride in fluorosis patients who drink elevated concentrations of fluoride in water.
		Lymphocyte sister chromatid exchange: A similar 0.4-mL sample of blood was incubated for 24 hr at 370C.
		Sister chromatid differentiation on staining was performed by the FPG technique.
	www.fluoridealert.org /sce-fluorosis.htm (1113 words)

	The Cell Cycle (Site not responding. Last check: 2007-10-20)
		A sister chromatid is one of two (a pair) of DNA double helices that result from the replication a single DNA double helix (as least as described in a eukaryotic cell).
		Sister chromatid pairs are joined at their centromeres.
		So long as the centromeres of a sister chromatid pair remain attached, the visible pair is described as a chromosome.
	www.mansfield.ohio-state.edu /~sabedon/campbl12.htm (1291 words)

	Dmitri Ivanov - How Does Cohesin Hold Sister Chromatids Together
		After a eukaryotic cell replicates its DNA it contains pairs of sister chromatids that have to be segregated to the daughter cells during cell division in a very precise manner.
		Since sister kinetochores (and the rest of the chromatids) are cohesed to each other, when the microtubules pull at the kinetochores tension is generated which is sensed by the checkpoint mechanism.
		If by mistake sister kinetochores are attached to microtubules that originate from the same spindle, there is no tension generated and such microtubule-kinetochore attachment is disrupted and corrected.
	mendel.imp.ac.at /home/ivanov/index.html (1030 words)

	Meiosis
		The distribution of recombinant and non-recombinant sister chromatids [View] into the daughter cells at anaphase II is also random.
		Double-stranded breaks (DSBs) often occur in the DNA of the chromatids, and these may be necessary for the homologs to recognize each other.
		sister chromatids during meiosis II Zygotes missing one chromosome ("monosomy") cannot develop to birth (except for females with a single X chromosome).
	users.rcn.com /jkimball.ma.ultranet/BiologyPages/M/Meiosis.html (1379 words)

	Structure of a palindromic amplicon junction implicates microhomology-mediated end joining as a mechanism of sister ...
		This is the junction between the two sister chromatids, which forms a region of microhomology between this region and the repeat region 4 kb upstream.
		Southern hybridization of CHOC 400 and CHO genomic DNA in the region of the sister chromatid fusion.
		The Mre11 complex then binds to the ends of the sister chromatids, and its 3' exonuclease activity exposes the 5' strands until regions of microhomology are reached, which stabilize the complex (33,34).
	nar.oxfordjournals.org /cgi/content/full/32/2/749 (4519 words)

	Effect of nitric oxide and malondialdehyde on sister-chromatid exchanges in breast cancer British Journal of Biomedical ... (Site not responding. Last check: 2007-10-20)
		Sister chromatid exchanges, indices of human chromosome damage and repair: detection by fluorescence and induction by mitomycin C. Proc Natl Acad Sci USA 1974; 71: 3162-6.
		Sister chromatid exchange as an indicator of mutagenesis.
		Induction of sister chromatid exchange in Chinese hamster ovary cells' by thiol and hydrazine compounds.
	www.findarticles.com /p/articles/mi_qa3874/is_200101/ai_n8952681 (600 words)

	Milestone 23 Making and breaking bonds between sisters
		Chromosomes are duplicated in S phase, but the two copies (sister chromatids) are kept together until much later, being pulled apart at the metaphase-to-anaphase transition during mitosis.
		Kim Nasmyth and colleagues started by reasoning that, if there is a protein-based glue that keeps sister chromatids together for much of the cell cycle, then that glue might be destroyed at the start of anaphase to allow chromatids to separate.
		Their screen for mutant yeasts in which sister chromatids can separate in the absence of APC function identified several proteins - three of which, Smc1, Smc3 and Scc1, are essential for cohesion.
	www.nature.com /celldivision/milestones/full/milestone23.html (755 words)

	Sister chromatid exchange test (Site not responding. Last check: 2007-10-20)
		Sister chromatid exchanges (SCEs) involve breakage of both DNA strands, followed by an exchange of whole DNA duplexes.
		To allow for a differential staining that enables the researcher to distinguish both chromatids, BrdU (bromo-deoxy-uridine) is added to the culture medium for the duration of two complete cell cycles.
		Chromatids in which only one strand of DNA incorporated BrdU show a normal dark Giemsa staining, whereas those with two substituted strands, stain less darkly.
	cdfc00.rug.ac.be /HealthRisk/genotoxicitytests/sister_chromatid_exchange_test.htm (269 words)

	The Scientist : A polymerase for sister chromatid cohesion
		Cohesins, the proteins that are thought to anchor sister chromatids to one another before anaphase, must be present during DNA replication if cohesion is to be established.
		They describe an essential DNA polymerase in budding yeast that both has polymerase activity and is required for sister chromatid cohesion.
		Cohesion between sister chromatids must be established during DNA replication.
	www.the-scientist.com /article/display/19081 (146 words)

	Ctf7p is essential for sister chromatid cohesion and links mitotic chromosome structure to the DNA replication ...
		Cohesion between replicated sister chromatids is fundamental to cell viability.
		Sister chromatid cohesion is apparently established during S phase and maintained until anaphase onset.
		We propose that the dissolution of sister chromatid cohesion
	www.genesdev.org /cgi/content/full/13/3/307 (6634 words)

	SWITCH1 (SWI1): a novel protein required for the establishment of sister chromatid cohesion and for bivalent formation ...
		Sister chromatid arm cohesion (I) and centromere cohesion were lost (J), leading to 20 separated chromatids at metaphase I (K).
		Kamieniecki, R.J., Shanks, R.M., and Dawson, D.S. Slk19p is necessary to prevent separation of sister chromatids in meiosis I. Curr.
		Skibbens, R.V., Corson, L.B., Koshland, D., and Hieter, P. Ctf7p is essential for sister chromatid cohesion and links mitotic chromosome structure to the DNA replication machinery.
	www.genesdev.org /cgi/content/full/15/14/1859 (7400 words)

	Faculty
		Through the analysis of factors that mediate chromosome condensation and sister chromatid cohesion during mitosis and meiosis, we hope to elucidate the underlying molecular mechanism of chromosome structure and the principles that govern chromosome evolution.
		From these analyses cohesins establish cohesion through a two step process first binding to specific chromosomal addresses on one sister chromatid, followed by activation through an auxiliary factor to establish cohesion with the second sister chromatid.
		Hartman, T., Stead, K., Koshland, D. and Guacci, V. Pds5p is an essential chromosomal protein required for both sister chromatid cohesion and condensation in Saccharomyces cerevisiae.
	www.bio.jhu.edu /Faculty/Koshland/Default.html (1073 words)

	The extent of sister chromatid cohesiveness in the centromere region of prophase II dyads
		The extent of sister chromatid cohesiveness in the centromere region of prophase II dyads
		If sister chromatids tend to cohere until anaphase II, except where they were separated at anaphase I as a result of crossing over, dyads would be expected to vary in their prophase II configuration in accordance with the position of their most proximal crossover in each arm.
		If the hypothesis is to be seriously considered, the most reasonable speculation might be that sister chromatid cohesiveness tends to be lost to some extent proximal to crossovers during the anaphase I to prophase II interval.
	www.agron.missouri.edu /mnl/52/81maguire.html (590 words)

	Genes Involved in Sister Chromatid Separation and Segregation in the Budding Yeast Saccharomyces cerevisiae -- Biggins ...
		Wild-type cells separate sister chromatids to opposite poles so there is a GFP signal in each bud.
		Sister chromatids do not separate as far apart in the smt3-331 mutant cells as they do in wild-type cells.
		sister chromatids in the absence of a spindle.
	www.genetics.org /cgi/content/full/159/2/453 (7775 words)

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