In plant organelle genomes, homeologous recombination between heteroallelic positions of repetitive sequences is increased by dysfunction of the gene encoding MutS homolog 1 (MSH1), a plant organelle-specific homolog of bacterial mismatch-binding protein MutS1. The C-terminal region of plant MSH1 contains the GIY-YIG endonuclease motif. The biochemical characteristics of plant MSH1 have not been investigated; accordingly, the molecular mechanism by which plant MSH1 suppresses homeologous recombination is unknown. Here, we characterized the recombinant GIY-YIG domain of Arabidopsis thaliana MSH1, showing that the domain possesses branched DNA-specific DNA-binding activity. Interestingly, the domain exhibited no endonuclease activity, suggesting that the mismatch-binding domain is required for DNA incision. Based on these results, we propose a possible mechanism for MSH1-dependent suppression of homeologous recombination.
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http://dx.doi.org/10.1002/1873-3468.13279 | DOI Listing |
Biochem Biophys Res Commun
May 2024
Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, Taiwan. Electronic address:
DNA mismatch repair (MMR) is a crucial mechanism that ensures chromosome stability and prevents the development of various human cancers. Apart from its role in correcting mismatches during DNA replication, MMR also plays a significant role in regulating recombination between non-identical sequences, a process known as homeologous recombination. Telomeres, the protective ends of eukaryotic chromosomes, possess sequences that are not perfectly homologous.
View Article and Find Full Text PDFFront Mol Biosci
August 2023
Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India.
The human malaria parasite maintains the chronicity of infections through antigenic variation, a well-coordinated immune evasion mechanism. The most prominent molecular determinant of antigenic variation in this parasite includes the members of the multigene family. Homologous recombination (HR)-mediated genomic rearrangements have been implicated to play a major role in gene diversification.
View Article and Find Full Text PDFFront Plant Sci
May 2023
Department of Bioscience, Universita degli Studi di Milano, Milan, Italy.
BMC Biol
May 2023
Life Sciences Department, Barcelona Supercomputing Center (BSC), Jordi Girona, 29, 08034, Barcelona, Spain.
Background: Hybrids are chimeric organisms with highly plastic heterozygous genomes that may confer unique traits enabling the adaptation to new environments. However, most evolutionary theory frameworks predict that the high levels of genetic heterozygosity present in hybrids from divergent parents are likely to result in numerous deleterious epistatic interactions. Under this scenario, selection is expected to favor recombination events resulting in loss of heterozygosity (LOH) affecting genes involved in such negative interactions.
View Article and Find Full Text PDFMethods Mol Biol
February 2023
Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
Whole-genome duplications yield varied chromosomal pairing patterns, ranging from strictly bivalent to multivalent, resulting in disomic and polysomic inheritance modes. In the bivalent case, homeologous chromosomes form pairs, where in a multivalent pattern all copies are homologous and are therefore free to pair and recombine. As sufficient sequencing data is more readily available than high-quality cytological assessments of meiotic behavior or population genetic assessment of allelic segregation, especially for non-model organisms, bioinformatics approaches to infer origins and inheritance modes of polyploids using short-read sequencing data are attractive.
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