Biology subjects

Iacopino, S.

Publications and source records attributed to Iacopino, S..

4 recordsLinked to original sources

bioRxiv2025

KDM7-mediated oxygen sensing reprograms chromatin to enhance hypoxia tolerance in the root

Roots frequently encounter low oxygen (hypoxia) from soil compaction or water saturation and must adapt to this stress. We investigated how root tip cells sense hypoxia and adjust the meristem epigenome to activate genes that promote tolerance and growth under oxygen limitation. In Arabidopsis root tips, hypoxia tolerance was linked to increased trimethylation of histone H3 at lysine 4 (H3K4me3). We also found that group 7 demethylases (KDM7s) are directly inhibited by hypoxia, and that genetic inactivation of KDM7s, like hypoxia, induces expression of genes essential for meristem survival under oxygen deprivation. We propose that KDM7s function as root-specific oxygen sensors that prime and support hypoxia tolerance.

plant biology↗

bioRxiv2024

Engineering prolyl hydroxylase-dependent proteolysis enables the orthogonal control of hypoxia responses in plants

Vascular plants and metazoans use selective proteolysis of transcription factors to control the adaptive responses to hypoxia, although through distinct biochemical mechanisms. The reason for this divergence is puzzling, especially when considering that the molecular components necessary to establish both strategies are conserved across the two kingdoms. To explore an alternative evolutionary scenario where plants sense hypoxia as animals do, we engineered a three-components system aimed to target proteins for degradation in an oxygen dependent manner in Arabidopsis thaliana. Applying the synthetic biology framework, we produced a hypoxia-responsive switch independent of endogenous pathways. When applied to control transcription, the synthetic system partially restored hypoxia responsiveness in oxygen-insensitive mutants. Additionally, we demonstrated its potential to regulate growth under flood-induced hypoxia. Our work highlights the use of synthetic biology to reprogram signalling pathways in plants, providing insights into the evolution of oxygen sensing and ofering tools for crop improvement under stress conditions.

synthetic biology↗

bioRxiv2021

A synthetic switch based on orange carotenoid protein to control blue light responses in chloroplasts

ABSTRACTSynthetic biology approaches to engineer light-responsive system are widely used, but their applications in plants are still limited, due to the interference with endogenous photoreceptors. Cyanobacteria, such as Synechocystis spp., possess a soluble carotenoid associated protein named Orange Carotenoid binding Protein (OCP) that, when activated by blue-green light, undergoes reversible conformational changes that enable photoprotection of the phycobilisomes. Exploiting this system, we developed a new chloroplast-localized synthetic photoswitch based on a photoreceptor-associated protein-fragment complementation assay (PCA). Since Arabidopsis thaliana does not possess the prosthetic group needed for the assembly of the OCP2 protein, we implemented the carotenoid biosynthetic pathway with a bacterial {beta}-carotene ketolase enzyme (crtW), to generate keto-carotenoids producing plants. The novel photoswitch was tested and characterized in Arabidopsis protoplasts with experiments aimed to uncover its regulation by light intensity, wavelength, and its conversion dynamics. We believe that this pioneer study establishes the basis for future implementation of plastid optogenetics to regulate organelle responses, such as gene transcription or enzymatic activity, upon exposure to specific light spectra. One-sentence summaryInspired by the light-driven conformational transitions of orange carotenoid proteins of cyanobacteria, we generated a molecular device able to switch its dimeric state in response to blue light.

synthetic biology↗

bioRxiv2020

Acquisition of hypoxia inducibility by oxygen sensing N-terminal cysteine oxidase in spermatophytes

N-terminal cysteine oxidases (NCOs) are enzymes that use molecular oxygen to oxidize the amino-terminal cysteine of specific proteins, thereby initiating the proteolytic N-degron pathway and thus conferring them oxygen-dependent instability. To expand the characterization of the plant family of NCOs (PCOs), we performed a phylogenetic analysis across different plant taxa in terms of sequence similarity and transcriptional regulation. Based on this survey, we propose a distinction of PCOs into two main groups: A-type and B-type sequences. A-type PCOs are conserved across all plant species and are generally unaffected at the mRNA level by oxygen availability. Instead, B-type PCOs differentiated in spermatophytes to acquire specific amino acid features and transcriptional regulation in response to hypoxia. Both groups of PCO proteins possess the ability to destabilize Cys-initiating proteins. Indeed, the inactivation of two A-type PCOs in Arabidopsis thaliana, PCO4 and PCO5, is sufficient to activate, at least partially, the anaerobic response in young seedlings, whereas the additional removal of B-type PCOs leads to a stronger induction of anaerobic genes and impairs plant growth and development. Our results show that both PCO types are required to regulate the anaerobic response in angiosperm. Therefore, while it is possible to distinguish two clades within the PCO family, separated by both amino acid features and transcriptional regulation, we conclude that they both contribute to restrain the anaerobic transcriptional program in normoxic conditions and together generate a molecular switch to toggle the hypoxic response in Arabidopsis.One sentence summary Hypoxic induction of Plant Cysteine Oxidases has been acquired and fixed in seed plants by ancestor proteins able to initiate the proteolysis of Cys-initiating protein substrates by the Arg/N-degron pathway.View Full Text

plant biology↗