Just recently, a high-throughput genetic screening of meiotic crossover rate mutants in Arabidopsis thaliana amassed the interest of the academic neighborhood by unraveling a century-old mystery in the life sciences.A research group, consisting of Professor Kyuha Choi, Dr. Jaeil Kim, and PhD candidate Heejin Kim from the Department of Life Sciences at Pohang University of Science and Technology (POSTECH), has actually achieved an impressive task by revealing the molecular system responsible for crossover interference throughout meiosis, a biological pattern at the chromosome level. Crossover disturbance, where one crossover prevents the development of another crossover close by along the same chromosome, was at first identified by fruit fly geneticist Hermann J. Muller in 1916. Regardless of researchers persistent efforts over the previous century since its discovery, it is just recently that the mechanisms underlying crossover interference have actually started to unveil their secrets.Breakthrough in Understanding Crossover InterferenceIn this research, the team used a high-throughput fluorescent seed scoring approach to straight measure crossover frequency in Arabidopsis plants. Further analysis revealed that the elevated crossovers in hcr3 was associated to a point anomaly in the J3 gene, which encodes a co-chaperone related to HSP40 protein.This research study demonstrated that a network involving HCR3/J3/HSP40 co-chaperone and the chaperone HSP70 controls crossover disturbance and localization by assisting in the destruction of the pro-crossover protein, HEI10 ubiquitin E3 ligase.
A research group from Pohang University of Science and Technology unveiled the system behind crossover interference throughout meiosis, resolving a long-standing mystery in genes. This advancement could change farming breeding by enabling accurate control over crop characteristics, paving the way for improved disease resistance and productivity in plants.Movies such as X-Men, Fantastic Four, and The Guardians, which showcase lively mutant heroes, have captivated international audiences. Recently, a high-throughput hereditary screening of meiotic crossover rate mutants in Arabidopsis thaliana amassed the interest of the academic neighborhood by unraveling a century-old secret in the life sciences.A research study group, consisting of Professor Kyuha Choi, Dr. Jaeil Kim, and PhD prospect Heejin Kim from the Department of Life Sciences at Pohang University of Science and Technology (POSTECH), has actually attained an impressive accomplishment by unveiling the molecular mechanism accountable for crossover interference throughout meiosis, a biological pattern at the chromosome level. The findings of this research study were published on February 20 in Nature Plants, a worldwide journal in the field of life sciences.The Role of Meiosis in Genetic DiversityIn sexually recreating organisms, individuals resemble their brother or sisters or parents. In spite of the striking resemblances, its crucial to acknowledge that absolute identicalness is unattainable. This variation is associated to the process of meiosis, which creates reproductive cells like sperm and eggs in animals or pollen and ovules in plants. Unlike somatic cell department, which replicates and divides the genome identically, meiosis creates genetically diverse reproductive cells through a system known as crossover.Meiosis and crossover play essential roles in biodiversity and have significant implications in breeding where the choice and growing of exceptional qualities in crops happen. Generally, most animal and plant types show a minimum of one and a maximum of 3 crossovers per a set of homologous chromosomes.a. Genetic isolation of hcr3 mutants utilizing a fluorescent seed crossover measurement system. b. Genomic crossover maps showing a 2-fold increase in crossover in J3G155R transgenic plants revealing hcr3 allele (highlighted in red) compared to the wild type (depicted in blue). c. hcr3 revealed an increased number of HEI10 foci and decreased range in between HEI10 foci per bivalent. d. Model highlighting control of HEI10 degradation-mediated crossover interference through the HCR3-HSP70 chaperone network. Credit: POSTECHThe ability to manage the number of these crossovers might result in cultivating crops with specific preferred traits. Achieving such control has actually been challenging due to the phenomenon of crossover disturbance. Crossover disturbance, where one crossover inhibits the development of another crossover close by along the same chromosome, was initially identified by fruit fly geneticist Hermann J. Muller in 1916. In spite of researchers persistent efforts over the previous century since its discovery, it is only just recently that the mechanisms underlying crossover interference have actually begun to unveil their secrets.Breakthrough in Understanding Crossover InterferenceIn this research, the group made use of a high-throughput fluorescent seed scoring approach to directly measure crossover frequency in Arabidopsis plants. Through a genetic screen, they recognized a mutant named hcr3 (high crossover rate3) that showed an increased crossover rate at the genomic level. Further analysis exposed that the elevated crossovers in hcr3 was credited to a point mutation in the J3 gene, which encodes a co-chaperone associated to HSP40 protein.This research demonstrated that a network involving HCR3/J3/HSP40 co-chaperone and the chaperone HSP70 manages crossover disturbance and localization by helping with the destruction of the pro-crossover protein, HEI10 ubiquitin E3 ligase. The application of genetic screen approaches to uncover the crossover interference and inhibition path effectively resolved a century-old puzzle in the life sciences.POSTECH Professor Kyuha Choi mentioned, “Applying this research to agriculture will allow us to quickly collect beneficial traits, consequently reducing reproducing time.” He expressed optimism by stating, “We hope this research study will contribute to the breeding of brand-new ranges and recognition of useful natural variations responsible for desirable qualities such as disease and ecological stress resistance, enhanced productivity, and high-value production.”Reference: “Control of meiotic crossover interference by a proteolytic chaperone network” by Heejin Kim, Jaeil Kim, Namil Son, Pallas Kuo, Chris Morgan, Aurélie Chambon, Dohwan Byun, Jihye Park, Youngkyung Lee, Yeong Mi Park, John A. Fozard, Julie Guérin, Aurélie Hurel, Christophe Lambing, Martin Howard, Ildoo Hwang, Raphael Mercier, Mathilde Grelon, Ian R. Henderson and Kyuha Choi, 20 February 2024, Nature Plants.DOI: 10.1038/ s41477-024-01633-yThe research study was carried out with assistance from the Basic Research Program in Science and Engineering and the Mid-Career Researcher Program of the National Research Foundation of Korea, the Next-Generation BioGreen 21 Program of the Rural Development Administration, the Suh Kyungbae Foundation, and the Samsung Science & & Technology Foundation.