Houda Benhelli

University of Nantes | UNIV Nantes · Département des Sciences de la Vie

To maintain its genome integrity, the cell uses complementary and orchestrated processes, among which is the DNA Damage Response. Pre mRNA maturation is an essential step of the DNA damage response that provides an adapted proteome in order to face genotoxic stress. We describe here a new phosphorylation of the RAD51 recombinase, on its Ser97 resid...

RAD51 is the central protein in DNA repair by homologous recombination (HR), involved in several steps of this process. It is shown that overexpression of the RAD51 protein is correlated with increased survival of cancer cells to cancer treatments. For the past decade, RAD51 overexpression-mediated resistance has justified the development of target...

Homologous recombination (HR) is involved in repairing DNA double-strand breaks (DSB), the most harmful for the cell. Regulating HR is essential for maintaining genomic stability. In many forms of cancer, overactivation of HR increases tumor resistance to DNA-damaging treatments. RAD51, HR's core protein, is very often over-expressed in these cance...

Background DNA dependent Protein Kinase (DNA-PK) is an heterotrimeric complex regulating the Non Homologous End Joining (NHEJ) double strand break (DSB) repair pathway. The activity of its catalytic subunit (DNA-PKcs) is regulated by multiple phosphorylations, like the Ser2056 one that impacts DSB end processing and telomeres integrity. O-GlcNAcyla...

Antibody microarrays have become a powerful tool in multiplexed immunoassay technologies. The advantage of microarray technology is the possibility of rapid analysis of multiple targets in a single sample with a high sensitivity, which makes them ideal for high throughput screening. Usually these microarrays contain biological recognition molecules...

Tauopathies such as Alzheimer's Disease (AD) are neurodegenerative disorders for which there is presently no cure. They are named after the abnormal oligomerization/aggregation of the neuronal microtubule-associated Tau protein. Besides its role as a microtubule-associated protein, a DNA-binding capacity and a nuclear localization for Tau protein h...

Therapeutic efficacy against cancer is often based on a variety of DNA lesions, including DNA double-strand breaks (DSBs) which are repaired by homologous recombination and non-homologous end joining (NHEJ) pathways. In the past decade, the functions of the DNA repair proteins have been described as a potential mechanism of resistance in tumor cell...

The field of optical bioimaging has considerably flourished with the advent of sophisticated microscopy techniques and ultra-bright fluorescent tools. Fluorescent organic nanoparticles (FONs) have thus recently appeared as very attractive labels for their high payload, their absence of cytotoxicity and eventual biodegradation. Nevertheless, their b...

Pericentromeric heterochromatin (PCH) gives rise to highly dense chromatin sub-structures rich in the epigenetic mark corresponding to the trimethylated form of lysine 9 of histone H3 (H3K9me3) and in heterochromatin protein 1α (HP1α), which regulate genome expression and stability. We demonstrate that Tau, a protein involved in a number of neurode...

High-density nanoarchitectures, endowed with simultaneous fluorescence and contrast properties for MRI and TEM imaging, have been obtained using a simple self-assembling strategy based on supramolecular interactions between non-doped fluorescent organic nanoparticles (FON) and superparamagnetic nanoparticles. In this way, a high-payload core-shell...

The expression and activity of DNA-dependent protein kinase (DNA-PK) is related to DNA repair status in the response of cells to exogenous and endogenous factors. Recent studies indicate that Epidermal Growth Factor Receptor (EGFR) is involved in modulating DNA-PK. It has been shown that a compound 4-nitro-7-[(1-oxidopyridin-2-yl)sulfanyl]-2,1,3-be...

Fluorescent organic nanoparticles (FONs), made of self-assembled solvatochromic fluorophores, represent a novel class of bright imaging agents. On page 2727, E. Ishow and co-workers show how in cellulo studies evidence dramatic dissembling of FONs by macrophages compared to cancer cells. Macrophages disintegrate internalized yellow-emitting FONs an...

Strongly solvatochromic fluorophores are devised, containing alkyl chains and enable to self-assemble as very bright fluorescent organic nanoparticles (FONs) in water (Φf = 0.28). The alkyl chains impart each fluorophore with strongly hydrophobic surroundings, causing distinct emission colors between FONs where the fluorophores are associated, and...

The capacity of endogenous Tau to bind DNA has been recently identified in neurons under physiological or oxidative stress conditions. Characterization of the protein domains involved in Tau-DNA complex formation is an essential first step to clarify the contribution of Tau-DNA interactions on neurological biological processes. To define the amino...

Ataxia Telangiectasia Mutated (ATM) and Ataxia Telangiectasia and Rad3-related (ATR) kinases are two key regulators of DNA-damage responses (DDR) that are mainly activated in response to DNA double-strand breaks and single-stranded DNA damages, respectively. Seckel Syndrome, a rare genetic disorder characterized by a microcephaly and a markedly red...

Nuclear architecture as well as gene nuclear positioning can modulate gene expression. In this work, we have analyzed the nuclear position of the interferon-β (IFN-β) locus, responsible for the establishment of the innate antiviral response, with respect to pericentromeric heterochromatin (PCH) in correlation with virus-induced IFN-β gene expressio...

Virus-induced activation of the beta interferon (IFN-β) gene requires orderly recruitment of chromatin-remodeling complexes and time-regulated acetylation of histone residues K8H4 and K14H3 on the promoter region. We have previously shown that transcription factor Yin Yang 1 (YY1) binds the murine IFN-β promoter at two sites (−122 and −90) regulati...

Pericentromeric γ-satellite DNA is organized in constitutive heterochromatin structures. It comprises a 234 bp sequence repeated several thousands times surrounding the centromeric sequence of all murine chromosomes. Potential binding sites for transcription factor Yin Yang 1 (YY1), a repressor or activator of several cellular and viral genes, are...