Simulation of chromosomal homology searching in meiotic pairing

Dorninger, Dietmar; Karigl, Günther; Loidl, Josef

doi:10.1006/jtbi.1995.0195

Cited by 16 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our simulations gave an entirely different result concerning the role of NE attachment than that predicted by [10], in that we see pairing is FASTER when the chromosomes are internal, not attached. We speculate this is because the telomeres do not diffuse freely in 2D on the surface because they are constrained through their attachment to the rest of the chromosome, which then acts like an anchor due to viscous drag.…”

Section: Discussioncontrasting

confidence: 85%

Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

Marshall¹,

Fung

2016

Phys. Biol.

View full text Add to dashboard Cite

The recognition and pairing of homologous chromosomes during meiosis is a complex physical and molecular process involving a combination of polymer dynamics and molecular recognition events. Two highly conserved features of meiotic chromosome behavior are the attachment of telomeres to the nuclear envelope and the active random motion of telomeres driven by their interaction with cytoskeletal motor proteins. Both of these features have been proposed to facilitate the process of homolog pairing, but exactly what role these features play in meiosis remains poorly understood. Here we investigate the roles of active motion and nuclear envelope tethering using a Brownian dynamics simulation in which meiotic chromosomes are represented by a Rouse polymer model subjected to tethering and active forces at the telomeres. We find that tethering telomeres to the nuclear envelope slows down pairing relative to the rates achieved by un-attached chromosomes, but that randomly-directed active forces applied to the telomeres speeds up pairing dramatically in a manner that depends on the statistical properties of the telomere force fluctuations. The increased rate of initial pairing cannot be explained by stretching out of the chromosome conformation but instead seems to correlate with anomalous diffusion of sub-telomeric regions.

show abstract

Section: Discussioncontrasting

confidence: 85%

Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

Marshall¹,

Fung

2016

Phys. Biol.

View full text Add to dashboard Cite

show abstract

“…Meiosis induction in the diploid SK1 strain and the tetraploid SK1 strain derived therefrom revealed that prophase I progression, bouquet formation and meiotic divisions were delayed in tetraploid meiosis compared with diploid wild-type meiosis -which contrasts with the situation in diploid versus allopolyploid plants (Martinez-Perez et al, 2000;Moore, 2002) and indicates that accelerated prophase I progression in polyploid plants is not a universal feature that extends to other kingdoms. Besides other possibilities, the prophase I delay in the polyploid yeast is in agreement with the assumption that a genome with increased chromosome number will require a more elaborate and time-consuming homologue search during prophase I (Dorninger et al, 1995;Pfeifer et al, 2001). How, then, according to such a scenario, is prophase I progression accelerated in polyploid plants?…”

Section: Discussionsupporting

confidence: 78%

Increased ploidy and KAR3 and SIR3 disruption alter the dynamics of meiotic chromosomes and telomeres

Trelles-Sticken

Loidl

Scherthan

2003

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

We investigated the sequence of chromosomal events during meiotic prophase in haploid, diploid and autotetraploid SK1 strains of Saccharomyces cerevisiae. Using molecular cytology, we found that meiosis-specific nuclear topology (i.e. dissolution of centromere clustering, bouquet formation and meiotic divisions) are significantly delayed in polyploid SK1 meiosis. Thus, and in contrast to the situation in plants, an increase in ploidy extends prophase I in budding yeast. Moreover, we found that bouquet formation also occurs in haploid and diploid SK1 meiosis deficient in the telomeric heterochromatin protein Sir3p. Diploid sir3Δ SK1 meiosis showed pleiotropic defects such as delayed centromere cluster resolution in a proportion of cells and impeded downstream events (i.e. bouquet formation,homologue pairing and meiotic divisions). Meiotic telomere clustering occurred in diploid and haploid sir3Δ strains. Using the haploid system,we further show that a bouquet forms at the kar3Δ SPB. Comparison of the expression of meiosis-specific Ndj1p-HA and Zip1p in haploid control and kar3Δ time courses revealed that fewer cells enter the meiotic cycle in absence of Kar3p. Elevated frequencies of bouquets in kar3Δ haploid meiosis suggest a role for Kar3p in regulation of telomere dynamics.

show abstract

“…Meiotic chromosome pairing probably employs sophisticated mechanisms for an efficient chromosome-wide homology screen, which excludes ectopic homologies from subsequent recombination. In most organisms homologous contacts first occur during meiotic prophase and it is possible that different organisms employ different strategies to facilitate these contacts (see Loidl, 1990;Loidl, 1994;Dorninger et al, 1995). In many organisms, all of the chromosome ends assemble within a limited area at the nuclear periphery.…”

Section: Introductionmentioning

confidence: 99%

Organization and pairing of meiotic chromosomes in the ciliateTetrahymena thermophila

Loidl

Scherthan²

2004

Journal of Cell Science

Self Cite

122

View full text Add to dashboard Cite

During meiotic prophase in the ciliate Tetrahymena thermophila micronuclei dramatically elongate and form thread-like crescents. The arrangement of the chromosomes within the crescent as well as the timing of chromosome pairing and recombination with respect to the elongation process have been subjects of ongoing debate. Here, we addressed these issues by means of fluorescence in situ hybridization, labeling of individual chromosomes by BrdU (BrdU-painting) and by immunostaining of the recombination protein, Rad51. BrdU-painting indicated that chromosomes are arranged as parallel bundles within the crescent, and telomere-directed fluorescent in situ hybridization (FISH) revealed that most if not all telomeres are assembled near one end of the developing crescent. Prior to full crescent formation, Rad51 localizes to chromatin as numerous foci. Locus-specific FISH demonstrated that close pairing of homologues only occurs in the full crescent. Meiotic DNA double-strand break formation and the initiation of recombination thus seem to precede close pairing. A synaptonemal complex was not detected. We conclude that the chromosomes adopt a polarized arrangement within the crescent, probably resembling the classical bouquet arrangement. Furthermore, we propose that the elongated shape of meiotic micronuclei promotes the parallel arrangement of chromosomes and supports the juxtaposition of homologous regions in the absence of a synaptonemal complex. Several pieces of evidence indicate the presence of one to four chiasmata per bivalent, which would call for crossover interference to explain regular bivalent formation in spite of this low mean number. Tetrahymena might, therefore, pose a case of interference in the absence of a synaptonemal complex.

show abstract

Simulation of chromosomal homology searching in meiotic pairing

Cited by 16 publications

References 0 publications

Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

Increased ploidy and KAR3 and SIR3 disruption alter the dynamics of meiotic chromosomes and telomeres

Organization and pairing of meiotic chromosomes in the ciliateTetrahymena thermophila

Contact Info

Product

Resources

About