Molecular mechanism of double Holliday junction dissolution

Abstract Current models for meiotic recombination require that crossovers derive from the resolution of a double-Holliday junction (dHJ) intermediate. In prokaryotes, enzymes responsible for HJ resolution are well characterized but the identification of a eukaryotic nuclear HJ resolvase has been elusive. Indirect evidence suggests that MUS81 from humans and fission yeast encodes a HJ resolvase. We provide three lines of evidence that Mus81/Mms4 is not the major meiotic HJ resolvase in S. cerevisiae: (1) MUS81/MMS4 is required to form only a distinct subset of crossovers; (2) rather than accumulating, dHJ intermediates are reduced in an mms4 mutant; and (3) expression of a bacterial HJ resolvase has no suppressive effect on mus81 meiotic phenotypes. Our analysis also reveals the existence of two distinct classes of crossovers in budding yeast. Class I is dependent upon MSH4/MSH5 and exhibits crossover interference, while class II is dependent upon MUS81/MMS4 and exhibits no interference. mms4 specifically reduces crossing over on small chromosomes, which are known to undergo less interference. The correlation between recombination rate and degree of interference to chromosome size may therefore be achieved by modulating the balance between class I/class II crossovers.

Download Full-text

Template disruptions and failure of double Holliday junction dissolution during double-strand break repair in Drosophila BLM mutants

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0607904103 ◽

2006 ◽

Vol 103 (45) ◽

pp. 16840-16845 ◽

Cited By ~ 24

Author(s):

D. Johnson-Schlitz ◽

W. R. Engels

Keyword(s):

Strand Break ◽

Double Strand Break ◽

Double Strand Break Repair ◽

Holliday Junction ◽

Break Repair ◽

Double Holliday Junction

Download Full-text

Regulation of Msh4-Msh5 association with meiotic chromosomes in budding yeast

Genetics ◽

10.1093/genetics/iyab102 ◽

2021 ◽

Author(s):

Krishnaprasad G Nandanan ◽

Sagar Salim ◽

Ajith V Pankajam ◽

Miki Shinohara ◽

Gen Lin ◽

...

Keyword(s):

Binding Sites ◽

Holliday Junction ◽

Crossing Over ◽

Wild Type ◽

Yeast Saccharomyces Cerevisiae ◽

Meiotic Chromosomes ◽

Genome Wide ◽

Double Holliday Junction

Abstract In the baker’s yeast Saccharomyces cerevisiae, most of the meiotic crossovers are generated through a pathway involving the highly conserved mismatch repair related Msh4-Msh5 complex. To understand the role of Msh4-Msh5 in meiotic crossing over, we determined its genome wide in vivo binding sites in meiotic cells. We show that Msh5 specifically associates with DSB hotspots, chromosome axes, and centromeres on chromosomes. A basal level of Msh5 association with these chromosomal features is observed even in the absence of DSB formation (spo11Δ mutant) at the early stages of meiosis. But efficient binding to DSB hotspots and chromosome axes requires DSB formation and resection and is enhanced by double Holliday junction structures. Msh5 binding is also correlated to DSB frequency and enhanced on small chromosomes with higher DSB and crossover density. The axis protein Red1 is required for Msh5 association with the chromosome axes and DSB hotspots but not centromeres. Although binding sites of Msh5 and other pro-crossover factors like Zip3 show extensive overlap, Msh5 associates with centromeres independent of Zip3. These results on Msh5 localization in wild type and meiotic mutants have implications for how Msh4-Msh5 works with other pro-crossover factors to ensure crossover formation.

Download Full-text

Faculty Opinions recommendation of The Mus81/Mms4 endonuclease acts independently of double-Holliday junction resolution to promote a distinct subset of crossovers during meiosis in budding yeast.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1016715.201242 ◽

2003 ◽

Author(s):

Gregory Copenhaver

Keyword(s):

Budding Yeast ◽

Holliday Junction ◽

Distinct Subset ◽

Double Holliday Junction

Download Full-text

Top3α Is Required during the Convergent Migration Step of Double Holliday Junction Dissolution

PLoS ONE ◽

10.1371/journal.pone.0083582 ◽

2014 ◽

Vol 9 (1) ◽

pp. e83582 ◽

Cited By ~ 8

Author(s):

Stefanie Hartman Chen ◽

Jody L. Plank ◽

Smaranda Willcox ◽

Jack D. Griffith ◽

Tao-shih Hsieh

Keyword(s):

Holliday Junction ◽

Double Holliday Junction

Download Full-text

Control of meiotic recombination in Arabidopsis: role of the MutL and MutS homologues

Biochemical Society Transactions ◽

10.1042/bst0340542 ◽

2006 ◽

Vol 34 (4) ◽

pp. 542-544 ◽

Cited By ~ 23

Author(s):

F.C.H. Franklin ◽

J.D. Higgins ◽

E. Sanchez-Moran ◽

S.J. Armstrong ◽

K.E. Osman ◽

...

Keyword(s):

Mismatch Repair ◽

Meiotic Recombination ◽

Holliday Junction ◽

Crossing Over ◽

Wild Type ◽

Pathway Model ◽

Junction Formation ◽

Double Holliday Junction ◽

Dependent Pathway

Immunocytochemistry reveals that the Arabidopsis mismatch repair proteins AtMSH4, AtMLH3 and AtMLH1 are expressed during prophase I of meiosis. Expression of AtMSH4 precedes AtMLH3 and AtMLH1 which co-localize as foci during pachytene. Co-localization between AtMSH4 and AtMLH3 occurs, but appears transient. AtMLH3 foci are not detected in an Atmsh4 mutant. However, localization of AtMSH4 is unaffected in Atmlh3, suggesting that recombination may proceed to dHj (double Holliday junction) formation. Mean chiasma frequency in Atmsh4 is reduced to 1.55 compared with 9.86 in wild-type. In contrast with wild-type, the distribution of residual crossovers in Atmsh4 closely fits a Poisson distribution. This is consistent with a two-pathway model for meiotic crossing-over whereby most crossovers occur via an AtMSH4-dependent pathway that is subject to interference, with the remaining crossovers arising via an interference-independent pathway. Loss of AtMLH3 results in an approx. 60% reduction in crossovers. Results suggest that dHj resolution can occur, but in contrast with wild-type where most or all dHjs are directed to form crossovers, the outcome is biased in favour of a non-crossover outcome. The results are compatible with a model whereby the MutL complex maintains or imposes a dHj conformation that ensures crossover formation.

Download Full-text

Exo1-protected DNA nicks direct crossover formation in meiosis

10.1101/2021.08.29.458102 ◽

2021 ◽

Author(s):

Michael Gioia ◽

Lisette Payero ◽

Gianno Pannafino ◽

Jun Jie Chen ◽

Sagar Salim ◽

...

Keyword(s):

Experimental Evidence ◽

Mismatch Repair ◽

Molecular Level ◽

Holliday Junction ◽

Crossing Over ◽

Structural Elements ◽

Crossover Interference ◽

Double Holliday Junction ◽

Dna Nicks ◽

Null Mutants

In most sexually reproducing organisms crossing over between chromosome homologs during meiosis is critical for the viability of haploid gametes. Most crossovers that form in meiosis in budding yeast result from the biased resolution of double Holliday Junction (dHJ) intermediates. This dHJ resolution step involves the actions Rad2/XPG family nuclease Exo1 and the Mlh1- Mlh3 mismatch repair endonuclease. At present little is known about how these factors act in meiosis at the molecular level. Here we show that Exo1 promotes meiotic crossing over by protecting DNA nicks from ligation. We found that structural elements in Exo1 required for interactions with DNA, such as bending of DNA during nick/flap recognition, are critical for its role in crossing over. Consistent with these observations, meiotic expression of the Rad2/XPG family member Rad27 partially rescued the crossover defect in exo1 null mutants, and meiotic overexpression of Cdc9 ligase specifically reduced the crossover levels of exo1 DNA binding mutants to levels approaching the exo1 null. In addition, our work identified a role for Exo1 in crossover interference that appears independent of its resection activity. Together, these studies provide experimental evidence for Exo1 protected nicks being critical for the formation of meiotic crossovers and their distribution.

Download Full-text