Biology subjects

PARCY, F.

Publications and source records attributed to PARCY, F..

4 recordsLinked to original sources

bioRxiv2026

A comprehensive Arabidopsis transcription factor binding atlas reveals pervasive positional and syntactic organization of their DNA binding

Transcription factor (TF) binding underlies gene regulation, yet the determinants of TF-DNA interactions across plant genomes remain incompletely understood. Here, we present a comprehensive atlas of TF binding in Arabidopsis thaliana, generated by reanalyzing 1,157 publicly available ChIP-seq and DAP/ampDAP-seq datasets using a unified processing framework. After stringent curation, 681 high-quality experiments were retained, providing binding information for 425 TFs across 42 families and 23 structural classes. Using this resource, we show that TF binding predictability varies widely across TFs, with family identity explaining substantially more variation in predictive performance than structural class. Among the tested TF binding site (TFBS) prediction models, deep learning approaches achieved the highest overall predictive accuracy, while classical position weight matrices remained competitive and readily interpretable. Beyond motif recognition, we uncover widespread organizational principles of TF binding. TFBS positioning relative to transcription start sites is strongly family-dependent and more concentrated near promoters in vivo. Moreover, preferred spacing between homotypic TFBS is pervasive across TF families, indicating that binding-site syntax is a general organizational feature of TF binding in plants. Comparison of in vivo and in vitro binding profiles further identifies a shared core of sequence-driven binding alongside in vivo-enriched sites associated with non-canonical or composite sequence features. Together, these results highlight the interplay between intrinsic DNA recognition, higher-order binding syntax, and cellular context in shaping TF binding landscapes, while providing a broadly useful resource for the plant community.

plant biology↗

bioRxiv2026

SEPALLATA MADS transcription factors act as key regulators in fertilization efficiency, ovule outer integument growth and mucilage secretory cell differentiation in Arabidopsis

In angiosperms, ovule development requires the activity of the C, D and E classes of MADS genes, which encode key transcriptional regulators of reproductive development. The SEPALLATA (SEP) MADS transcription factors (MTFs), which belong to the E class, act as organizing hubs of MADS heterotetrameric complexes and play an essential role in the development of flower organs. However, the role of the SEP genes in ovule and seed development has been difficult to determine due to redundancy in the subclade, the lack of observable phenotypes in single and double sep1 sep2 mutants and the homeotic conversion of the carpel into sepal or leaf in higher order sep mutants. Here, we engineered a version of SEP3 (SEP3{Delta}M) that encodes a protein lacking the DNA-binding MADS-domain but retains the oligomerization domains needed for MADS protein heterotetramerization. In vitro experiments demonstrated the ability of SEP3{Delta}M to interact with the C and D classes of MTF, reducing the capability of such MADS complex to efficiently bind DNA. sep3{Delta}M plants showed a delay in flower opening and organ maturation and a reduced fertility. The ovules exhibited reduced outer integument growth, and the few seeds that developed showed impaired mucilage secretion upon imbibition. RNA-seq analysis of sep3{Delta}M demonstrated misregulation of genes involved in outer integument and seed coat development. Taken together, these data indicate the key role of SEP3-containing MADS complexes in proper ovule outer integument growth and seed coat development.

plant biology↗

bioRxiv2026

Structural Evolution of LEAFY Reveals DNA-Mediated Cooperativity and Dimerization Shifts at the Water-to-Land Transition

The evolution of transcription factor (TF) DNA-binding specificity is a major driver of gene regulatory innovation. Unlike most TFs, which diversify through gene duplication and neofunctionalization, the plant-specific LEAFY (LFY) TF evolved novel binding specificities without extensive duplication. Here, we combine experimental structural determination and biochemical assays to reveal how LFYs dimerization and DNA-binding preferences shifted during the water-to-land transition. We present crystal structures of the LFY DNA-binding domain (DBD) from the hornwort Nothoceros aenigmaticus and the alga Interfilum paradoxum bound to DNA, demonstrating two distinct dimerization mechanisms: one mediated by direct protein-protein interactions and another driven by DNA-mediated cooperativity. In the ancestral state, LFY likely bound DNA as a dimer through DNA-mediated cooperativity, with protein-protein dimerization emerging later, enforcing new DNA-binding preferences. Our findings support a revised evolutionary scenario for LFY, highlighting the dynamic interplay between protein-DNA and protein-protein interactions as key drivers of TF binding specificity. This work deepens our understanding of how structural adaptations in TFs underpin evolutionary transitions in gene regulation.

plant biology↗

bioRxiv2022

The F-box cofactor UFO redirects the LEAFY floral regulator to novel cis-elements

In angiosperms, flower patterning requires the localized expression of the APETALA3 (AP3) floral homeotic gene involved in petal and stamen development. AP3 is synergistically induced by the master transcription factor (TF) LEAFY (LFY) and the F-box protein UNUSUAL FLORAL ORGANS (UFO), but the molecular mechanism underlying this synergy has remained unknown. Here we show that the connection to ubiquitination pathways suggested by the F-box domain of UFO is mostly dispensable for its function and that UFO instead acts by forming a transcriptional complex with LFY and binds to newly discovered regulatory elements. Cryo-electron microscopy explains how a LFY-UFO complex forms on these novel DNA sites due to direct interaction of UFO with LFY and DNA. Finally, we show that this complex has a deep evolutionary origin, largely predating flowering plants. This work reveals a novel mechanism of an F-box protein in directly modulating the DNA-binding specificity of a master TF.

plant biology↗