Similar Sister Chromatid Arrangement in Mono- and Holocentric Plant Chromosomes

2016 ◽  
Vol 149 (3) ◽  
pp. 218-225 ◽  
Author(s):  
Veit Schubert ◽  
Mateusz Zelkowski ◽  
Sonja Klemme ◽  
Andreas Houben
Keyword(s):  
Sister Chromatid ◽  
Chromosome Complement ◽  
Super Resolution ◽  
Sister Chromatid Exchanges ◽  
Holocentric Chromosomes ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Plant Chromosomes ◽  
Sister Chromatids ◽  
Chromatid Exchanges

Due to the X-shape formation at somatic metaphase, the arrangement of the sister chromatids is obvious in monocentric chromosomes. In contrast, the sister chromatids of holocentric chromosomes cannot be distinguished even at mitotic metaphase. To clarify their organization, we differentially labelled the sister chromatids of holocentric Luzula and monocentric rye chromosomes by incorporating the base analogue EdU during replication. Using super-resolution structured illumination microscopy (SIM) and 3D rendering, we found that holocentric sister chromatids attach to each other at their contact surfaces similar to those of monocentrics in prometaphase. We found that sister chromatid exchanges (SCEs) are distributed homogeneously along the whole holocentric chromosomes of Luzula, and that their occurrence is increased compared to monocentric rye chromosomes. The SCE frequency of supernumerary B chromosomes, present additionally to the essential A chromosome complement of rye, does not differ from that of A chromosomes. Based on these results, models of the sister chromatid arrangement in mono- and holocentric plant chromosomes are presented.

scholarly journals Automatic detection and localization of sister chromatid exchanges.

1976 ◽  
Vol 24 (1) ◽  
pp. 168-177 ◽  
Author(s):  
G W Zack ◽  
J A Spriet ◽  
S A Latt ◽  
G H Granlund ◽  
I T Young
Keyword(s):  
Computer Analysis ◽  
Sister Chromatid ◽  
Automatic Detection ◽  
Sister Chromatid Exchanges ◽  
Banding Patterns ◽  
Sister Chromatids ◽  
Manual Methods ◽  
Detection And Localization ◽  
Chromatid Exchanges

Sister chromatids of human metaphase chromsomes from cells which have replicated twice in medium containing 5-bromodeoxyuridine exhibit unequal fluorescence when stained with the dye 33258 Hoechst. Sister chromatid exchanges occurring in these chromosomes are apparent as interchanges of brightly and dully fluorescing chromatids. A technique for detecting such exchanges by computer analysis of chromsome images has been developed and found to campare favorably with manual methods. The exchanges have been localized in the context of quinacrine banding patterns.

DIFFERENTIAL FLUORESCENCE OF SISTER CHROMATIDS WITH 4′-6-DIAMIDINO-2-PHENYLINDOLE

1976 ◽  
Vol 18 (3) ◽  
pp. 545-547 ◽  
Author(s):  
M. S. Lin ◽  
O. S. Alfi ◽  
G. N. Donnell
Keyword(s):  
Fluorescence Microscopy ◽  
Sister Chromatid ◽  
Human Lymphocytes ◽  
Sister Chromatid Exchanges ◽  
Sister Chromatids ◽  
Chromatid Exchanges ◽  
Dapi Fluorescence ◽  
Sensitive Method

Differential fluorescence of sister chromatids and sister chromatid exchanges (SCE) in chromosomes from human lymphocytes grown two replication cycles in medium containing 5-bromodeoxyuridine can be detected by fluorescence microscopy after staining with 4′-6-diamidino-2-phenylindole (DAPI). The DAPI fluorescence appears to be more stable than that of the dye 33258 Hoechst and may provide a more sensitive method for the detection of SCE.

scholarly journals Meiotic sister chromatid exchanges are rare in C. elegans

2020 ◽  
Author(s):  
David E. Almanzar ◽  
Spencer G. Gordon ◽  
Ofer Rog
Keyword(s):  
Sister Chromatid ◽  
Homologous Chromosome ◽  
Sister Chromatid Exchanges ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
C Elegans ◽  
Sister Chromatids ◽  
Repair Template ◽  
Almost All ◽  
Chromatid Exchanges

AbstractSexual reproduction shuffles the parental genomes to generate new genetic combinations. To achieve that, the genome is subjected to numerous double-strand breaks, the repair of which involves two crucial decisions: repair pathway and repair template. Use of crossover pathways with the homologous chromosome as template exchanges genetic information and directs chromosome segregation. Crossover repair, however, can compromise the integrity of the repair template and is therefore tightly regulated. The extent to which crossover pathways are used during sister-directed repair is unclear, because the identical sister chromatids are difficult to distinguish. Nonetheless, indirect assays have led to the suggestion that inter-sister crossovers, or sister chromatid exchanges (SCEs), are quite common. Here we devised a technique to directly score physiological SCEs in the C. elegans germline using selective sister chromatid labeling with the thymidine analog 5-ethynyl-2’-deoxyuridine (EdU). Surprisingly, we find SCEs to be rare in meiosis, accounting for <2% of repair events. SCEs remain rare even when the homologous chromosome is unavailable, indicating that almost all sister-directed repair is channeled into noncrossover pathways. We identify two mechanisms that limit SCEs. First, sister-directed repair intermediates are efficiently inhibited by the RecQ helicase BLMHIM-6. Second, the Synaptonemal Complex–a conserved interface that promotes crossover repair– localizes between the homologous chromosomes and not the sister chromatids. Our data suggest that in C. elegans crossover pathways are only used to generate the single necessary link between the homologous chromosomes. Almost all other breaks, regardless of which repair template they use, are repaired by noncrossover pathways.

scholarly journals SISTER CHROMATID EXCHANGE IN XERODERMA PIGMENTOSUM CELLS THAT ARE DEFECTIVE IN DNA EXCISION REPAIR OR POST-REPLICATION REPAIR

Genetics ◽  
1975 ◽  
Vol 81 (2) ◽  
pp. 349-355
Author(s):  
Sheldon Wolff ◽  
Judy Bodycote ◽  
G H Thomas ◽  
James E Cleaver
Keyword(s):  
Dna Repair ◽  
Sister Chromatid ◽  
Xeroderma Pigmentosum ◽  
Excision Repair ◽  
Sister Chromatid Exchanges ◽  
Normal Limits ◽  
Repair Enzymes ◽  
Sister Chromatids ◽  
Post Replication Repair ◽  
Chromatid Exchanges

ABSTRACT The formation of sister chromatid exchanges has been postulated to depend upon the action of DNA repair enzymes. Our experiments with various human cell lines show that the yield of sister chromatid exchanges is within normal limits in both excision-repair-defective and post-replication-repair-defective cells from the autosomal recessive disease, xeroderma pigmentosum. These results indicate that hypotheses invoking known DNA repair processes to account for the recombination of sister chromatids are inadequate and that the exact enzymatic processes are as yet unknown.

LACK OF SPONTANEOUS SISTER CHROMATID EXCHANGES IN SOMATIC CELLS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1979 ◽  
Vol 91 (2) ◽  
pp. 255-274
Author(s):  
M Gatti ◽  
G Santini ◽  
S Pimpinelli ◽  
G Olivieri
Keyword(s):  
Drosophila Melanogaster ◽  
Sister Chromatid ◽  
Ring Chromosome ◽  
Sister Chromatid Exchanges ◽  
The Other ◽  
Hoechst 33258 ◽  
Wild Type ◽  
X Chromosomes ◽  
Sister Chromatids ◽  
Chromatid Exchanges

ABSTRACT Neural ganglia of wild type third-instar larvae of Drosophila melanogasier were incubated for 13 hours at various concentrations of BUdR (1, 3, 9, 27 μg/ml) . Metaphases were collected with colchicine, stained with Hoechst 33258, and scored under a fluorescence microscope. Metaphases in which the sister chromatids were clearly differentiated were scored for the presence of sister-chromatid exchanges (SCEs) . At the lowest concentration of BUdR (1 μg/ml), no SCEs were observed in either male or female neuroblasts. The SCEs were found at the higher concentrations of BUdR (3, 9 and 27 μg/ml) and with a greater frequency in females than in males. Therefore SCEs are not a spontaneous phenomenon in D. melanogasier, but are induced by BUdR incorporated in the DNA. A striking nonrandomness was found in the distribution of SCEs along the chromosomes. More than a third of the SCEs were clustered in the junctions between euchromatin and heterochromatin. The remaining SCEs were preferentially localized within the heterochromatic regions of the X chromosome and the autosomes and primarily on the entirely heterochromatic Y chromosome.—In order to find an alternative way of measuring the frequency of SCEs in Drosophila neuroblasts, the occurrence of double dicentric rings was studied in two stocks carrying monocentric ring-X chromosomes. One ring chromosome, C(I)TR94-2, shows a rate of dicentric ring formation corresponding to the frequency of SCEs observed in the BUdR-labelled rod chromosomes. The other ring studied, R(1)2, exhibits a frequency of SCEs higher than that observed with both C(I)TR94-2 and rod chromosomes.

Diagnostic Ultrasound and Sister Chromatid Exchanges

1985 ◽  
Vol 40 (9) ◽  
pp. 589-590
Author(s):  
V. CIARAVINO ◽  
A. BRULFERT ◽  
M. W. MILLER ◽  
D. JACOBSON-KRAM ◽  
W. F. MORGAN
Keyword(s):  
Sister Chromatid ◽  
Diagnostic Ultrasound ◽  
Sister Chromatid Exchanges ◽  
Chromatid Exchanges

scholarly journals Two-dimensional TIRF-SIM–traction force microscopy (2D TIRF-SIM-TFM)

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liliana Barbieri ◽  
Huw Colin-York ◽  
Kseniya Korobchevskaya ◽  
Di Li ◽  
Deanna L. Wolfson ◽  
...  
Keyword(s):  
Resolution Enhancement ◽  
Traction Force ◽  
Super Resolution ◽  
Traction Force Microscopy ◽  
Two Dimensional ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Force Microscopy ◽  
Health And Disease ◽  
Spatio Temporal

AbstractQuantifying small, rapidly evolving forces generated by cells is a major challenge for the understanding of biomechanics and mechanobiology in health and disease. Traction force microscopy remains one of the most broadly applied force probing technologies but typically restricts itself to slow events over seconds and micron-scale displacements. Here, we improve >2-fold spatially and >10-fold temporally the resolution of planar cellular force probing compared to its related conventional modalities by combining fast two-dimensional total internal reflection fluorescence super-resolution structured illumination microscopy and traction force microscopy. This live-cell 2D TIRF-SIM-TFM methodology offers a combination of spatio-temporal resolution enhancement relevant to forces on the nano- and sub-second scales, opening up new aspects of mechanobiology to analysis.

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