Limits...
Leptotene/zygotene chromosome movement via the SUN/KASH protein bridge in Caenorhabditis elegans.

Baudrimont A, Penkner A, Woglar A, Machacek T, Wegrostek C, Gloggnitzer J, Fridkin A, Klein F, Gruenbaum Y, Pasierbek P, Jantsch V - PLoS Genet. (2010)

Bottom Line: Abrogation of synapsis led to a deceleration of SUN-1 aggregate movement.Analysis of matefin/SUN-1 in a double-strand break deficient mutant revealed that repair intermediates influenced matefin/SUN-1 aggregate dynamics.Investigation of movement in meiotic regulator mutants substantiated that proper orchestration of the meiotic program and effective repair of DNA double-strand breaks were necessary for the wild-type behavior of matefin/SUN-1 aggregates.

View Article: PubMed Central - PubMed

Affiliation: Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.

ABSTRACT
The Caenorhabditis elegans inner nuclear envelope protein matefin/SUN-1 plays a conserved, pivotal role in the process of genome haploidization. CHK-2-dependent phosphorylation of SUN-1 regulates homologous chromosome pairing and interhomolog recombination in Caenorhabditis elegans. Using time-lapse microscopy, we characterized the movement of matefin/SUN-1::GFP aggregates (the equivalent of chromosomal attachment plaques) and showed that the dynamics of matefin/SUN-1 aggregates remained unchanged throughout leptonene/zygotene, despite the progression of pairing. Movement of SUN-1 aggregates correlated with chromatin polarization. We also analyzed the requirements for the formation of movement-competent matefin/SUN-1 aggregates in the context of chromosome structure and found that chromosome axes were required to produce wild-type numbers of attachment plaques. Abrogation of synapsis led to a deceleration of SUN-1 aggregate movement. Analysis of matefin/SUN-1 in a double-strand break deficient mutant revealed that repair intermediates influenced matefin/SUN-1 aggregate dynamics. Investigation of movement in meiotic regulator mutants substantiated that proper orchestration of the meiotic program and effective repair of DNA double-strand breaks were necessary for the wild-type behavior of matefin/SUN-1 aggregates.

Show MeSH

Related in: MedlinePlus

Dynamics of fusion/splitting events of SUN-1 aggregates for all genotypes studied (15 min recording).(A) Number of SUN-1 fusion/splitting events grouped into classes. (B) Quantification of the coalescence time (t) grouped into classes (t<1 min, 1 min≤t<3 min, and t≥3 min).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2991264&req=5

pgen-1001219-g002: Dynamics of fusion/splitting events of SUN-1 aggregates for all genotypes studied (15 min recording).(A) Number of SUN-1 fusion/splitting events grouped into classes. (B) Quantification of the coalescence time (t) grouped into classes (t<1 min, 1 min≤t<3 min, and t≥3 min).

Mentions: Because SUN-1 aggregates appeared to transiently coalesce (Figure 1A), we counted the number of fusion or splitting events of the aggregates during the first 15 min of the recordings (Figure 2A). The two most representative classes for the number of fusion/splitting events were 1–5 and 6–10 fusion/splitting events during the 15 min measuring period. A representative number of nuclei displayed between 11–15 fusion/splitting events, with an observed maximum of 25 exchanges. To assess how often exchanges take place, we looked at the time period between two fusion/splitting events. The “coalescence time” between aggregates was <1 min before splitting/fusing in 71% of cases, 1–3 min in 22% of cases, and >3 min in 7% of cases (Figure 2B).


Leptotene/zygotene chromosome movement via the SUN/KASH protein bridge in Caenorhabditis elegans.

Baudrimont A, Penkner A, Woglar A, Machacek T, Wegrostek C, Gloggnitzer J, Fridkin A, Klein F, Gruenbaum Y, Pasierbek P, Jantsch V - PLoS Genet. (2010)

Dynamics of fusion/splitting events of SUN-1 aggregates for all genotypes studied (15 min recording).(A) Number of SUN-1 fusion/splitting events grouped into classes. (B) Quantification of the coalescence time (t) grouped into classes (t<1 min, 1 min≤t<3 min, and t≥3 min).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991264&req=5

pgen-1001219-g002: Dynamics of fusion/splitting events of SUN-1 aggregates for all genotypes studied (15 min recording).(A) Number of SUN-1 fusion/splitting events grouped into classes. (B) Quantification of the coalescence time (t) grouped into classes (t<1 min, 1 min≤t<3 min, and t≥3 min).
Mentions: Because SUN-1 aggregates appeared to transiently coalesce (Figure 1A), we counted the number of fusion or splitting events of the aggregates during the first 15 min of the recordings (Figure 2A). The two most representative classes for the number of fusion/splitting events were 1–5 and 6–10 fusion/splitting events during the 15 min measuring period. A representative number of nuclei displayed between 11–15 fusion/splitting events, with an observed maximum of 25 exchanges. To assess how often exchanges take place, we looked at the time period between two fusion/splitting events. The “coalescence time” between aggregates was <1 min before splitting/fusing in 71% of cases, 1–3 min in 22% of cases, and >3 min in 7% of cases (Figure 2B).

Bottom Line: Abrogation of synapsis led to a deceleration of SUN-1 aggregate movement.Analysis of matefin/SUN-1 in a double-strand break deficient mutant revealed that repair intermediates influenced matefin/SUN-1 aggregate dynamics.Investigation of movement in meiotic regulator mutants substantiated that proper orchestration of the meiotic program and effective repair of DNA double-strand breaks were necessary for the wild-type behavior of matefin/SUN-1 aggregates.

View Article: PubMed Central - PubMed

Affiliation: Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.

ABSTRACT
The Caenorhabditis elegans inner nuclear envelope protein matefin/SUN-1 plays a conserved, pivotal role in the process of genome haploidization. CHK-2-dependent phosphorylation of SUN-1 regulates homologous chromosome pairing and interhomolog recombination in Caenorhabditis elegans. Using time-lapse microscopy, we characterized the movement of matefin/SUN-1::GFP aggregates (the equivalent of chromosomal attachment plaques) and showed that the dynamics of matefin/SUN-1 aggregates remained unchanged throughout leptonene/zygotene, despite the progression of pairing. Movement of SUN-1 aggregates correlated with chromatin polarization. We also analyzed the requirements for the formation of movement-competent matefin/SUN-1 aggregates in the context of chromosome structure and found that chromosome axes were required to produce wild-type numbers of attachment plaques. Abrogation of synapsis led to a deceleration of SUN-1 aggregate movement. Analysis of matefin/SUN-1 in a double-strand break deficient mutant revealed that repair intermediates influenced matefin/SUN-1 aggregate dynamics. Investigation of movement in meiotic regulator mutants substantiated that proper orchestration of the meiotic program and effective repair of DNA double-strand breaks were necessary for the wild-type behavior of matefin/SUN-1 aggregates.

Show MeSH
Related in: MedlinePlus