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Transcription dynamically patterns the meiotic chromosome-axis interface.

Sun X, Huang L, Markowitz TE, Blitzblau HG, Chen D, Klein F, Hochwagen A - Elife (2015)

Bottom Line: We found that the axial element proteins of budding yeast are flexibly anchored to chromatin by the ring-like cohesin complex.Importantly, axis anchoring by cohesin is adjustable and readily displaced in the direction of transcription by the transcriptional machinery.We propose that such robust but flexible tethering allows the axial element to promote recombination while easily adapting to changes in chromosome activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, New York University, New York, United States.

ABSTRACT
Meiotic chromosomes are highly compacted yet remain transcriptionally active. To understand how chromosome folding accommodates transcription, we investigated the assembly of the axial element, the proteinaceous structure that compacts meiotic chromosomes and promotes recombination and fertility. We found that the axial element proteins of budding yeast are flexibly anchored to chromatin by the ring-like cohesin complex. The ubiquitous presence of cohesin at sites of convergent transcription provides well-dispersed points for axis attachment and thus chromosome compaction. Axis protein enrichment at these sites directly correlates with the propensity for recombination initiation nearby. A separate modulating mechanism that requires the conserved axial-element component Hop1 biases axis protein binding towards small chromosomes. Importantly, axis anchoring by cohesin is adjustable and readily displaced in the direction of transcription by the transcriptional machinery. We propose that such robust but flexible tethering allows the axial element to promote recombination while easily adapting to changes in chromosome activity.

No MeSH data available.


Related in: MedlinePlus

Analysis of axis protein binding.(A) ChIP-qPCR analysis of axis proteins at selected positions in the indicated mutant backgrounds was performed with the precipitated DNA of the respective ChIP-seq experiment, before library amplification, for independent assessment of relative scaling of different profiles as shown in Figure 5. Gray bars indicate signal independent of the respective tag (V5-Red1 or Rec8-HA) or antibody (hop1∆). X-axis labels indicate genomic positions of primer pairs. (B) Averaged densities of V5-Red1 ChIP-seq signals over all 16 yeast centromeres, aligned at their midpoints. Two rather low V5-Red1 peaks (green) flank the centromere midpoint at a distance of around 220 bp. rec8∆ mutants (brown) or rec8∆ hop1∆ double mutants (purple) show reduced peaks. (C) The meiotic axis remodeler Pch2 is not responsible for the loss of interaction of Hop1 (or Red1) with Rec8 in red1∆ (or hop1∆) mutants, respectively. Upper panels: detection of interaction at 4 hr in SPM using anti-H3K9me3 antibody. Lower panels: total Hop1-HA-H3 (Red1-HA-H3) protein as determined by Western against the HA tag.DOI:http://dx.doi.org/10.7554/eLife.07424.011
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fig5s1: Analysis of axis protein binding.(A) ChIP-qPCR analysis of axis proteins at selected positions in the indicated mutant backgrounds was performed with the precipitated DNA of the respective ChIP-seq experiment, before library amplification, for independent assessment of relative scaling of different profiles as shown in Figure 5. Gray bars indicate signal independent of the respective tag (V5-Red1 or Rec8-HA) or antibody (hop1∆). X-axis labels indicate genomic positions of primer pairs. (B) Averaged densities of V5-Red1 ChIP-seq signals over all 16 yeast centromeres, aligned at their midpoints. Two rather low V5-Red1 peaks (green) flank the centromere midpoint at a distance of around 220 bp. rec8∆ mutants (brown) or rec8∆ hop1∆ double mutants (purple) show reduced peaks. (C) The meiotic axis remodeler Pch2 is not responsible for the loss of interaction of Hop1 (or Red1) with Rec8 in red1∆ (or hop1∆) mutants, respectively. Upper panels: detection of interaction at 4 hr in SPM using anti-H3K9me3 antibody. Lower panels: total Hop1-HA-H3 (Red1-HA-H3) protein as determined by Western against the HA tag.DOI:http://dx.doi.org/10.7554/eLife.07424.011

Mentions: We also observed increased Red1 binding near centromeres in hop1Δ mutants. A doublet of small V5-Red1 peaks was found to flank the yeast centromeres at a stereotypic distance of about 270 bp from their centers (Figure 5F). In rec8Δ and rec8Δ hop1Δ double mutants, these peaks were strongly decreased or missing (Figure 5—figure supplement 1B). By contrast, in hop1Δ mutants, the centromere proximal peaks of Red1 were strongly enhanced (Figure 5F), suggesting that Rec8 recruits Red1 next to the centromere against negative regulation by Hop1, which may in turn possibly prevent unwanted centromere proximal recombination.


Transcription dynamically patterns the meiotic chromosome-axis interface.

Sun X, Huang L, Markowitz TE, Blitzblau HG, Chen D, Klein F, Hochwagen A - Elife (2015)

Analysis of axis protein binding.(A) ChIP-qPCR analysis of axis proteins at selected positions in the indicated mutant backgrounds was performed with the precipitated DNA of the respective ChIP-seq experiment, before library amplification, for independent assessment of relative scaling of different profiles as shown in Figure 5. Gray bars indicate signal independent of the respective tag (V5-Red1 or Rec8-HA) or antibody (hop1∆). X-axis labels indicate genomic positions of primer pairs. (B) Averaged densities of V5-Red1 ChIP-seq signals over all 16 yeast centromeres, aligned at their midpoints. Two rather low V5-Red1 peaks (green) flank the centromere midpoint at a distance of around 220 bp. rec8∆ mutants (brown) or rec8∆ hop1∆ double mutants (purple) show reduced peaks. (C) The meiotic axis remodeler Pch2 is not responsible for the loss of interaction of Hop1 (or Red1) with Rec8 in red1∆ (or hop1∆) mutants, respectively. Upper panels: detection of interaction at 4 hr in SPM using anti-H3K9me3 antibody. Lower panels: total Hop1-HA-H3 (Red1-HA-H3) protein as determined by Western against the HA tag.DOI:http://dx.doi.org/10.7554/eLife.07424.011
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4530585&req=5

fig5s1: Analysis of axis protein binding.(A) ChIP-qPCR analysis of axis proteins at selected positions in the indicated mutant backgrounds was performed with the precipitated DNA of the respective ChIP-seq experiment, before library amplification, for independent assessment of relative scaling of different profiles as shown in Figure 5. Gray bars indicate signal independent of the respective tag (V5-Red1 or Rec8-HA) or antibody (hop1∆). X-axis labels indicate genomic positions of primer pairs. (B) Averaged densities of V5-Red1 ChIP-seq signals over all 16 yeast centromeres, aligned at their midpoints. Two rather low V5-Red1 peaks (green) flank the centromere midpoint at a distance of around 220 bp. rec8∆ mutants (brown) or rec8∆ hop1∆ double mutants (purple) show reduced peaks. (C) The meiotic axis remodeler Pch2 is not responsible for the loss of interaction of Hop1 (or Red1) with Rec8 in red1∆ (or hop1∆) mutants, respectively. Upper panels: detection of interaction at 4 hr in SPM using anti-H3K9me3 antibody. Lower panels: total Hop1-HA-H3 (Red1-HA-H3) protein as determined by Western against the HA tag.DOI:http://dx.doi.org/10.7554/eLife.07424.011
Mentions: We also observed increased Red1 binding near centromeres in hop1Δ mutants. A doublet of small V5-Red1 peaks was found to flank the yeast centromeres at a stereotypic distance of about 270 bp from their centers (Figure 5F). In rec8Δ and rec8Δ hop1Δ double mutants, these peaks were strongly decreased or missing (Figure 5—figure supplement 1B). By contrast, in hop1Δ mutants, the centromere proximal peaks of Red1 were strongly enhanced (Figure 5F), suggesting that Rec8 recruits Red1 next to the centromere against negative regulation by Hop1, which may in turn possibly prevent unwanted centromere proximal recombination.

Bottom Line: We found that the axial element proteins of budding yeast are flexibly anchored to chromatin by the ring-like cohesin complex.Importantly, axis anchoring by cohesin is adjustable and readily displaced in the direction of transcription by the transcriptional machinery.We propose that such robust but flexible tethering allows the axial element to promote recombination while easily adapting to changes in chromosome activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, New York University, New York, United States.

ABSTRACT
Meiotic chromosomes are highly compacted yet remain transcriptionally active. To understand how chromosome folding accommodates transcription, we investigated the assembly of the axial element, the proteinaceous structure that compacts meiotic chromosomes and promotes recombination and fertility. We found that the axial element proteins of budding yeast are flexibly anchored to chromatin by the ring-like cohesin complex. The ubiquitous presence of cohesin at sites of convergent transcription provides well-dispersed points for axis attachment and thus chromosome compaction. Axis protein enrichment at these sites directly correlates with the propensity for recombination initiation nearby. A separate modulating mechanism that requires the conserved axial-element component Hop1 biases axis protein binding towards small chromosomes. Importantly, axis anchoring by cohesin is adjustable and readily displaced in the direction of transcription by the transcriptional machinery. We propose that such robust but flexible tethering allows the axial element to promote recombination while easily adapting to changes in chromosome activity.

No MeSH data available.


Related in: MedlinePlus