Biology subjects

Mancini, I.

Publications and source records attributed to Mancini, I..

4 recordsLinked to original sources

bioRxiv2025

The EGY1-SGR1 module controls chloroplast development and senescence by modulating photosynthetic functions

The chloroplast plays essential roles not only in production of biochemical energy and metabolism, but also in plant development, including senescence. We describe a mutant with an unusual progression of senescence and identify it as an allele of ethylene-dependent gravitropism-deficient and yellow-green 1 (egy1-5). EGY1 encodes a chloroplast-localized metalloprotease that regulates chlorophyll metabolism. The single egy1-5 mutant exhibits defects in various aspects of chloroplast function, including abnormal accumulation of photosynthetic complexes, defects in photosynthetic electron transfer chain and altered responses to the chemicals methyl viologen and lincomycin. Additionally, egy1 lacks guard cell chloroplasts. We performed a suppressor mutant screen in the egy1 background to identify new regulators of senescence and chloroplast development. We found two suppressors that restored green leaves and mapping revealed that both suppressors had mutations in STAY-GREEN 1 (SGR1). SGR1 encodes the Mg2+ dechelatase enzyme, which catalyses the first step in chlorophyll breakdown. Several defects in the egy1 mutant were either fully or partially suppressed in egy1 sgr1. This enabled the function of EGY1 to be isolated, independent of the pleiotropic effects of chlorophyll degradation. Our findings suggest that chlorophyll homeostasis regulates the overall development and function of the chloroplast as well as plant senescence. HighlightIdentifying new mutants with defects in chlorophyll metabolism and chloroplast development shows that proper chlorophyll homeostasis is necessary for maintaining functional chloroplasts.

plant biology↗

bioRxiv2024

New insight on DNA isolation from single automated recovered Ceratocystis platani conidia

Single-cell technology is increasingly used to analyze the basis of molecular regulation and provide insights into different aspects of human diseases. Such technology is a breakthrough approach to study blood cancers by characterizing molecular information on a genome-wide scale at the single-cell level. These methods can be easily and successfully transferred to tracheomycotic plant pathogens, which cause host wilt. Ceratocystis platani is the causal agent of the Canker stain disease of plane tree (Platanus spp.), a lethal wilt disease spreading in Europe. To displace and separate different C. platani conidia types a dielectrophoretic approach was tested. The DNA of each conidium was isolated and analyzed and the target DNA was identified by a specific qPCR marker and by sequencing the amplicon. Our results showed that this technology is applicable to vascular plant pathogens. The fungal DNA was successfully extracted from single or pooled conidia and identified by both methods after whole genome amplification. The use of the single-cell technology will provide a new approach to the study of plant vascular diseases, allowing the study of single-spore molecular and physiological features not detectable in complex biological mixtures. Author summaryIn recent years, technologies for single-cell isolation have been developed in the study of human diseases, such as cancers, capable of obtaining genetic information at the single-cell level. In this study, these methods were transferred to a plant pathogen, Ceratocystis platani, which causes a lethal disease of plane tree. The single cell technique used was able to separate the different types of conidia of C. platani and analyze the DNA within each conidium. The use of single cell technology represents an important tool for the study of plant vascular diseases by allowing the study of molecular mechanisms that are difficult to detect in complex biological matrices.

pathology↗

bioRxiv2020

PHARMACOLOGICAL PROTEIN INACTIVATION BY TARGETING FOLDING INTERMEDIATES

Recent computational advancements in the simulation of biochemical processes allow investigating the mechanisms involved in protein regulation with realistic physics-based models, at an atomistic level of resolution. Using these techniques to study the negative regulation of the androgen receptor (AR), we discovered a key functional role played by non-native metastable states appearing along the folding pathway of this protein. This unexpected observation inspired us to design a completely novel drug discovery approach, named Pharmacological Protein Inactivation by Folding Intermediate Targeting (PPI-FIT), based on the rationale of negatively regulating protein expression by targeting folding intermediates. Here, PPI-FIT was tested for the first time on the cellular prion protein (PrP), a cell surface glycoprotein playing a key role in fatal and transmissible neurodegenerative pathologies known as prion diseases. We predicted the all-atom structure of an intermediate appearing along the folding pathway of PrP, and identified four different small molecule ligands for this conformer, all capable of selectively lowering the expression of the protein by promoting its degradation. Our data support the notion that the level of target proteins could be modulated by acting on their folding pathways, implying a previously unappreciated role for folding intermediates in the biological regulation of protein expression.

biochemistry↗

bioRxiv2019

GUN1 influences the accumulation of NEP-dependent transcripts and chloroplast protein import in Arabidopsis cotyledons upon perturbation of chloroplast protein homeostasis

Correct chloroplast development and function require coordinated expression of chloroplast and nuclear genes. This is achieved through chloroplast signals that modulate nuclear gene expression in accordance with the chloroplasts needs. Genetic evidence indicates that GUN1, a chloroplast-localized pentatricopeptide-repeat (PPR) protein with a C-terminal Small MutS-Related (SMR) domain, is involved in integrating multiple developmental and stress-related signals in both young seedlings and adult leaves. Recently, GUN1 was found to interact physically with factors involved in chloroplast protein homeostasis, and with enzymes of tetrapyrrole biosynthesis in adult leaves that function in various retrograde signaling pathways. Here we show that, following perturbation of chloroplast protein homeostasis i) by growth in lincomycin-containing medium, or ii) in mutants defective in either the FtsH protease complex (ftsh), plastid ribosome activity (prps21-1 and prpl11-1) or plastid protein import and folding (cphsp70-1), GUN1 influences NEP-dependent transcript accumulation during cotyledon greening and also intervenes in chloroplast protein import.

plant biology↗