Biology subjects

Fernandez-Capetillo, O.

Publications and source records attributed to Fernandez-Capetillo, O..

3 recordsLinked to original sources

bioRxiv2018

DNA and RNA binding mediate the toxicity of arginine-rich peptides encoded by C9ORF72 GGGGCC repeats

Due to their capability to transport chemicals or proteins into target cells, cell-penetrating peptides (CPPs) are being developed as therapy delivery tools. However, and despite their interesting properties, arginine-rich CPPs often show toxicity for reasons that remain poorly understood. Using a (PR)n dipeptide repeat that has been linked to amyotrophic-lateral sclerosis (ALS) as a model of an arginine-rich CPP, we here show that the presence of (PR)n leads to a generalized displacement of RNA- and DNA-binding proteins from chromatin and mRNA. Accordingly, any reaction involving nucleic acids such as RNA transcription, translation, splicing and degradation or DNA replication and repair are impaired by the presence of the CPP. Interestingly, the effects of (PR)n are fully mimicked by PROTAMINE, a small arginine-rich protein that displaces histones from chromatin during spermatogenesis. We propose that widespread coating of nucleic acids and consequent displacement of RNA- and DNA-binding factors from chromatin and mRNA accounts for the toxicity of arginine-rich CPPs, including those that have been recently associated to the onset of ALS.

neuroscience↗

bioRxiv2018

USP7 couples DNA replication termination to mitotic entry.

To ensure a faithful segregation of chromosomes, DNA must be fully replicated before mitotic entry. However, how cells sense the completion of DNA replication and to what extent this is linked to the activation of the mitotic machinery remains poorly understood. We previously showed that USP7 is a replisome-associated deubiquitinase with an essential role in DNA replication. Here, we reveal that USP7 inhibition leads to the ubiquitination of MCM7, a hallmark of DNA replication termination. In addition, USP7 inhibition leads to the ubiquitination of additional replisome components such as POLD1, which are displaced from replisomes. Surprisingly, this premature termination of DNA replication occurs concomitant to a generalized activation of CDK1 throughout the entire cell cycle, which impairs chromosome segregation and is toxic for mammalian cells. Accordingly, the toxicity of USP7 inhibitors is alleviated by CDK1 inhibition. Our work sheds light into the mechanism of action of USP7 inhibitors and provides evidence to the concept that DNA replication termination is coupled to the activation of the mitotic program.

cell biology↗

bioRxiv2017

ATR Is Required To Complete Meiotic Recombination In Mice

Precise execution of recombination during meiosis is essential for forming chromosomally balanced gametes. Meiotic recombination initiates with the formation and resection of DNA double-strand breaks (DSBs). Binding of replication protein A (RPA) at resected DSBs fosters association of RAD51 and DMC1, the primary effectors of homology search. It is well appreciated that cellular responses to meiotic DSBs are critical for efficient repair and quality control, but molecular features of these responses remain poorly understood, particularly in mammals. Here we provide evidence that the DNA damage response protein kinase ATR is crucial for meiotic recombination and completion of meiotic prophase in mice. Using a hypomorphic Atr mutation and pharmacological inhibition of ATR in vivo and in cultured spermatocytes, we show that ATR, through its effector kinase CHK1, promotes efficient RAD51 and DMC1 assembly at RPA-coated DSB sites and establishment of interhomolog connections during meiosis. Furthermore, our findings suggest that ATR promotes local accumulation of recombination markers on unsynapsed axes during meiotic prophase to favor homologous chromosome synapsis. These data reveal that ATR plays multiple roles in mammalian meiotic recombination.

cell biology↗