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Single-Molecule DNA Analysis Reveals That Yeast Hop1 Protein Promotes DNA Folding and Synapsis: Implications for Condensation of Meiotic Chromosomes

Khan, Krishnendu and Karthikeyan, Usha and Li, You and Yan, Jie and Muniyappa, K (2012) Single-Molecule DNA Analysis Reveals That Yeast Hop1 Protein Promotes DNA Folding and Synapsis: Implications for Condensation of Meiotic Chromosomes. In: ACS NANO, 6 (12). pp. 10658-10666.

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Official URL: http://dx.doi.org/10.1021/nn3038258


During meiosis, long-range interaction between homologous chromosomes is thought to be crucial for homology recognition, exchange of DNA strands, and production of normal haploid gametes. However, little is known about the identity of the proteins involved and the actual molecular mechanism(s) by which chromosomes recognize and recombine with their appropriate homologous partners. Single-molecule analyses have the potential to provide insights into our understanding of this fascinating and long-standing question. Using atomic force microscopy and magnetic tweezers techniques, we discovered that Hop1 protein, a key structural component of Saccharomyces cerevisiae synaptonemal complex, exhibits the ability to bridge noncontiguous DNA segments into intramolecular stem-loop structures in which the DNA segments appear to be fully synapsed within the filamentous protein stems. Additional evidence suggests that Hop1 folds DNA into rigid protein DNA filaments and higher-order nucleoprotein structures. Importantly, Hop1 promotes robust intra- and intermolecular synapsis between double-stranded DNA molecules, suggesting that juxtaposition of DNA sequences may assist in strand exchange between homologues by recombination-associated proteins. Finally, the evidence from ensemble experiments is consistent with the notion that Hop1 causes rigidification of DNA molecules. These results provide the first direct evidence for long-range protein-mediated DNA DNA synapsis, independent of crossover recombination, which is presumed to occur during meiotic recombination.

Item Type: Journal Article
Publication: ACS NANO
Additional Information: Copyright for this article belongs to AMER CHEMICAL SOC, WASHINGTON, USA
Keywords: meiosis;Hop1 protein;DNA bridging;DNA condensation;long-range DNA interactions;Holliday junction
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 23 Jan 2013 09:15
Last Modified: 23 Jan 2013 09:15
URI: http://eprints.iisc.ac.in/id/eprint/45669

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