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Home » Arabidopsis mutant hcr3 reveals role of J3 gene in regulating crossover interference during meiosis

Arabidopsis mutant hcr3 reveals role of J3 gene in regulating crossover interference during meiosis

A groundbreaking high-throughput screening of meiotic crossover rate mutants in Arabidopsis thaliana has finally unraveled a century-old enigma in the life sciences, shedding light on the intricate governing crossover interference during meiosis.

Led by Professor Kyuha Choi, Dr. Jaeil Kim, and Ph.D. candidate Heejin Kim from the Department of Life Sciences at Pohang University of Science and Technology (POSTECH), this research unveils the molecular intricacies underlying crossover interference, a crucial at the chromosome level during meiosis.

The findings of this research were published on February 20 in Nature Plants.

Meiosis, the process responsible for generating reproductive cells like and in animals or pollen and ovules in plants, is pivotal in introducing genetic diversity into . Unlike somatic , which duplicates and divides the genome identically, meiosis fosters genetically diverse reproductive cells through crossovers.

The significance of meiosis and crossover extends to biodiversity and breeding, where the cultivation of superior traits in crops relies on understanding and manipulating these processes.

Traditionally, organisms exhibit one to three crossovers per pair of homologous , yet controlling their frequency has proven challenging due to crossover interference – a phenomenon first identified by fruit fly geneticist Hermann J. Muller in 1916. Despite a century of investigation, unraveling the mechanisms behind crossover interference has remained elusive until now.

Employing a high-throughput fluorescent seed scoring method, the team directly measured crossover frequency in Arabidopsis plants, leading to the identification of a mutant named hcr3 (high crossover rate3) with an elevated crossover rate at the genomic level.

Further analysis pinpointed a point in the J3 gene, encoding a co-chaperone related to the HSP40 protein, as the culprit behind the increased crossovers in hcr3. The study elucidates a network involving HCR3/J3/HSP40 co-chaperone and the chaperone HSP70, which regulates crossover interference and localization by promoting the degradation of the pro-crossover protein, HEI10 ubiquitin E3 ligase.

This research's application of genetic screen approaches has finally cracked the code on crossover interference and inhibition, resolving a long-standing mystery in the life sciences.

Professor Kyuha Choi of POSTECH emphasizes, “Translating these findings to holds immense promise, accelerating the accumulation of beneficial traits and reducing breeding time. We envision this research will revolutionize the breeding of new crop varieties and identify valuable natural variations responsible for traits such as disease and stress resistance, enhanced productivity, and high-value yields.”

Source: Pohang University of Science and Technology