Biology subjects

Rosselli, F.

Publications and source records attributed to Rosselli, F..

3 recordsLinked to original sources

bioRxiv2025

The protein-protein interaction landscape of Fanconi anemia protein A (FANCA) reveals its contributions to mRNA processes.

Fanconi Anemia (FA) is a rare inherited recessive disorder characterized by bone marrow failure, congenital abnormalities, and a predisposition to myeloid leukemia and some solid cancers. FA is caused by mutations in one of the 22 so-called FANC genes, with two thirds of FA patients being FANCA mutants. FANC proteins cooperate within the FANC/BRCA pathway, a DNA repair system essential for resolving DNA interstrand crosslinks (ICLs) in S-phase. The canonical understanding of FA pathogenesis involves genome instability and impaired cellular proliferation due to DNA damage accumulation and stress response overactivation. However, recent data shows FANCA has a function in ribosome biogenesis and translation, which prompts a reassessment of FANCAs role(s) in cellular physiology and FA pathogenesis. We reasoned that unveiling the multiple interactions of the FANCA protein would shed light on these potentially new FANCA functions. By combining immunoprecipitation and BioID approaches, in three different cell lines and with different in silico analysis methods, we constructed lists of FANCA interactome proteins of different levels of selectivity and assembled them into a novel multilayered FANCA protein-protein interaction (PPI) landscape. Strikingly, we find that FANCA associates with proteins involved in processes distinct from DNA repair, such as translation, ribosome biogenesis, mRNA splicing, nucleocytoplasmic transport, chromatin remodeling, and the TCA cycle. We then analyzed the protein content of polysome profiling fractions and found that FANCA loss may affect ribosomal protein stoichiometry within ribosomal subunits. Overall, our data expands FANCAs PPI network far beyond the previously reported interactions. Importantly, we confirm the biological significance of low-selectivity interactions and propose to re-evaluate their importance in proteomic studies. The study of previously unsuspected FANCA functions, such as translation, could provide new therapeutic targets in FA and therefore improve patient care.

genetics↗

bioRxiv2023

The balance between ATR and DDK activities controls TopBP1-mediated locking of dormant origins at the pre-IC stage

Replication stress, a major hallmark of cancers, and ensuing genome instability source from impaired progression of replication forks. The first line of defense against fork slowing is compensation, a long-described process that elicits firing of otherwise dormant origins. It remains unclear whether compensation requires activation of the DNA replication checkpoint or passively results from lengthening of the window of time during which dormant origins can fire when fork progression slows, or both. Using molecular DNA combing we show here that a linear relationship ties inter-origin distances to fork speeds, independently of the checkpoint status. We called this line "stressline" and further show that its slope enables precise quantification of the compensation efficiency. Comparison of the slopes in different genetic backgrounds reveals that compensation requires ATR, not CHK1, while TopBP1 and CDC7/DBF4 repress dormant origin activation. These results strongly suggest that TopBP1 locks dormant origins at the pre-IC stage and that ATR and DDK oppose to control the conversion of dormant pre-ICs into functional salvage origins. Both passive and active processes thus contribute to compensation. Moreover, Repli-seq and OK-seq analyses confirm the activating role of ATR and permit development of ATRAP-seq, a new procedure allowing mapping of early constitutive origins.

genetics↗

bioRxiv2019

Fanconi anemia proteins are required to maintain nucleolar homeostasis.

The majority of inherited bone marrow failure (iBMF) syndromes are associated to nucleolar and/or ribosomal abnormalities, but Fanconi anemia (FA), the most common iBMF, is attributed to alterations in DNA damage responses. However, the involvement, if any, of the FA (FANC) proteins in the maintenance of nucleolar functions and/or ribosome biogenesis is yet unexplored. Here, we report that FANC pathway loss-of-function is associated to a loss of the nucleolar homeostasis, demonstrating increased rDNA rearrangements, accumulation of nucleolar DNA damage, nucleolar protein mislocalization, and a p53-independent induction of the growth inhibitory protein p21. Moreover, specifically associated to FANCA loss-of-function, which is responsible for approximately 65% of FA cases, we observed reduced rDNA transcription and rRNA processing as well as alteration in protein synthesis and polysome profiles. Thus, we have identified nucleolar consequences associated with FANC pathway deficiency, challenging current hypothesis on the physiopathology of FA.

cell biology↗