Nomoto, S. | bioRxiv Science

bioRxiv2026

The circadian clock gates lateral root development

Lateral root (LR) formation remodels root architecture, yet how temporal information integrates with hormonal cues remains unclear. We show that the circadian clock component EARLY FLOWERING 3 (ELF3) acts as a temporal gatekeeper of root organogenesis in Arabidopsis thaliana. Time-resolved transcriptomics, imaging, and genetics reveal that ELF3 restrains hormone-induced pericycle proliferation by maintaining rhythmic expression of key regulators under callus-inducing conditions. Loss of ELF3 disrupts rhythmic gene expression, enhancing callus growth and accelerating LR development. ELF3 functions through its target LNK1 to regulate the MADS-box genes AGL14 and AGL20. Notably, callus-inducing signals partially restore rhythmicity in elf3 mutants, revealing feedback from hormonal signaling to the circadian system. These findings identify ELF3 as an integrator of circadian and hormonal inputs that temporally constrains root developmental plasticity.

plant biology↗

bioRxiv2020

Importin α2 associates with chromatin via a novel DNA binding domain

Nuclear transport of proteins is important for facilitating appropriate nuclear functions. The proteins of the importin family play key roles in nuclear transport as transport receptors for a huge number of nuclear proteins. Additionally, these proteins possess other functions, including chromatin association and gene regulation. However, these non-transport functions of importin are not yet fully understood, especially their molecular-level mechanisms for functioning with chromatin and their consequences. Here, we report the novel molecular characteristics of importin involving binding to diverse sequences in chromatin. We newly identified and characterized a DNA-binding domain--the Nucleic Acid Associating Trolley pole domain (NAAT domain)--in the N-terminal region of importin within the conventional importin {beta} binding (IBB) domain, which was shown to be necessary for nuclear transport of cargo proteins. We propose a stroll and locate model to explain the association of importin with chromatin. This is the first study to delineate the interaction between importin and chromatin DNA via the NAAT domain, indicating the bifunctionality of the importin N-terminal region for nuclear transport and chromatin association.

molecular biology↗