Random single chromatid and nonrandom double chromatid type segregation of human acrocentric chromosomes in BrdU-labeled mitoses

1984 ◽  
Vol 26 (2) ◽  
pp. 137-140 ◽  
Author(s):  
S. Chemitiganti ◽  
R. S. Verma ◽  
S. Ved Brat ◽  
H. Dosik
Keyword(s):  
Human Leukocytes ◽  
Satellite Association ◽  
Chromatid Segregation ◽  
Random Segregation ◽  
Acrocentric Chromosomes ◽  
Single Chromatid ◽  
Cis And Trans

Chromatid segregation was analyzed using satellite association of 5-bromodeoxyuridine (BrdU) differentially stained acrocentric chromosomes of human leukocytes. Data were classified into cis and trans configurations in second and third division cycles. It was found that single chromatid types have random segregation (1:1) while nonrandom segregation was noted for double chromatid types. The nonrandom segregation hypothesis of earlier investigators needs to be reexamined.Key words: chromatid segregation, BrdU, mitosis, acrocentric.

N-Band polymorphism of human acrocentric chromosomes and its relevance to satellite association

1977 ◽  
Vol 36 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Isamu Hayata ◽  
Mitsuo Oshimura ◽  
Avery A. Sandberg
Keyword(s):  
Satellite Association ◽  
Acrocentric Chromosomes

SATELLITE ASSOCIATION IN HUMAN LYMPHOCYTES AND SODIUM CITRATE CONCENTRATION OF HYPOTONIC (SPREADING) SOLUTION

1971 ◽  
Vol 13 (1) ◽  
pp. 115-118 ◽  
Author(s):  
Howard R. Nankin
Keyword(s):  
Sodium Citrate ◽  
Human Lymphocytes ◽  
Satellite Association ◽  
Citrate Concentration ◽  
Acrocentric Chromosomes ◽  
The Relationship

The present investigation examined the relationship between satellite association in lymphocytes and sodium citrate concentration of the hypotonic solutions used to aid in spreading chromosomes. With reduction of sodium citrate from 0.9%, to 0.75%, and to 0.6%, the percentage of acrocentric chromosomes engaged in satellite association went from 32.7%, to 26.8%, and to 19.1% respectively. The reductions appeared to be equally divided between the D group and G group chromosomes.

scholarly journals Random segregation of chromatids at mitosis in Saccharomyces cerevisiae.

Genetics ◽  
1991 ◽  
Vol 127 (3) ◽  
pp. 463-473 ◽  
Author(s):  
M W Neff ◽  
D J Burke
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sister Chromatid ◽  
Mitotic Chromosome ◽  
Sister Chromatid Exchanges ◽  
Daughter Cells ◽  
Quantitative Measurements ◽  
Chromatid Segregation ◽  
Dna Strands ◽  
Random Segregation ◽  
Chromatid Exchanges

Abstract Previous experiments suggest that mitotic chromosome segregation in some fungi is a nonrandom process in which chromatids of the same replicative age are destined for cosegregation. We have investigated the pattern of chromatid segregation in Saccharomyces cerevisiae by labeling the DNA of a strain auxotrophic for thymidine with 5-bromodeoxyuridine. The fate of DNA strands was followed qualitatively by immunofluorescence microscopy and quantitatively by microphotometry using an anti-5-bromodeoxyuridine monoclonal antibody. Chromatids of the same replicative age were distributed randomly to daughter cells at mitosis. Quantitative measurements showed that the amount of fluorescence in the daughter nuclei derived from parents with hemilabeled chromosomes diminished in intensity by one half. The concentration of 5-bromodeoxyuridine used in the experiments had little effect on the frequency of either homologous or sister chromatid exchanges. We infer that the 5-bromodeoxyuridine was distributed randomly due to mitotic segregation of chromatids and not via sister chromatid exchanges.

scholarly journals DISTRIBUTION OF LABELED CHROMATIN

1970 ◽  
Vol 47 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Jean H. Priest ◽  
Robert H. Shikes
Keyword(s):  
Mammalian Cells ◽  
Tritiated Thymidine ◽  
Daughter Cells ◽  
Chromatid Segregation ◽  
Count Distribution ◽  
Random Segregation ◽  
Single Grain ◽  
Discrete Populations ◽  
Rule Out ◽  
Diploid Human Fibroblast

The question of whether distribution of chromatids to daughter cells in mitosis is a random or nonrandom process was investigated by study of the distribution of labeled chromatin in anaphase pairs at M1 and M2 after a pulse of tritiated thymidine. Diploid and tetraploid rat and diploid human fibroblast-like cells in serial monlayer culture were synchronized by two different methods to "purify" M1 and M2 anaphases: metaphase shake, and FUdR block to DNA synthesis followed by exogenous thymidine. Exposed grains of NTB-2 emulsion were counted over M1 and M2 anaphase pairs. An analysis (by pair) of diploid M2 anaphase grain counts showed two discrete populations of daughters with less and with more radioactivity. A similar analysis of diploid M1 and tetrapolid M2 anaphases showed a single grain-count distribution. These findings may support a nonrandom model of chromatid segregation for diploid mammalian cells but do not rule out random segregation until sound mathematical models are formulated for expected random grain distributions in M2 anaphases of cells with differing numbers of chromosomes.

A role for upstream binding factor in organizing ribosomal gene chromatin

2006 ◽  
Vol 73 ◽  
pp. 77-84 ◽  
Author(s):  
Jane E. Wright ◽  
Christine Mais ◽  
José-Luis Prieto ◽  
Brian McStay
Keyword(s):  
Nucleolar Organizer ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Nucleolar Organizer Regions ◽  
Binding Factor ◽  
Upstream Binding Factor ◽  
Acrocentric Chromosomes ◽  
Polymerase I ◽  
Secondary Constrictions ◽  
Active Nors

Human ribosomal genes are located in NORs (nucleolar organizer regions) on the short arms of acrocentric chromosomes. During metaphase, previously active NORs appear as prominent chromosomal features termed secondary constrictions, which are achromatic in chromosome banding and positive in silver staining. The architectural RNA polymerase I transcription factor UBF (upstream binding factor) binds extensively across the ribosomal gene repeat throughout the cell cycle. Evidence that UBF underpins NOR structure is provided by an examination of cell lines in which large arrays of a heterologous UBF binding sequences are integrated at ectopic sites on human chromosomes. These arrays efficiently recruit UBF even to sites outside the nucleolus, and during metaphase form novel silver-stainable secondary constrictions, termed pseudo-NORs, that are morphologically similar to NORs.

Trypanocidal Structure-Activity Relationshipfor Cis- and Trans-methylpluviatolide

Planta Medica ◽  
2008 ◽  
Vol 74 (03) ◽  
Author(s):  
R Silva ◽  
J Saraiva ◽  
S Albuquerque ◽  
C Curti ◽  
PM Donate ◽  
...  
Keyword(s):  
Structure Activity ◽  
Cis And Trans
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