Biology subjects

Tessari, A.

Publications and source records attributed to Tessari, A..

6 recordsLinked to original sources

bioRxiv2024

Nucleolin acute degradation reveals novel functions in cell cycle progression and division in TNBC

Nucleoli are large nuclear sub-compartments where vital processes, such as ribosome assembly, take place. Technical obstacles still limit our understanding of the biological functions of nucleolar proteins in cell homeostasis and cancer pathogenesis. Since most nucleolar proteins are essential, their abrogation cannot be achieved through conventional approaches. Additionally, the biological activities of many nucleolar proteins are connected to their physiological concentration. Thus, artificial overexpression might not fully recapitulate their endogenous functions. Proteolysis-based approaches, such as the Auxin Inducible Degron (AID) system paired with CRISPR/Cas9 knock-in gene-editing, have the potential to overcome these limitations, providing unprecedented characterization of the biological activities of endogenous nucleolar proteins. We applied this system to endogenous nucleolin (NCL), one of the most abundant nucleolar proteins, and characterized the impact of its acute depletion on Triple-Negative Breast Cancer (TNBC) cell behavior. Abrogation of endogenous NCL reduced proliferation and caused defective cytokinesis, resulting in bi-nucleated tetraploid cells. Bioinformatic analysis of patient data, and quantitative proteomics using our experimental NCL-depleted model, indicated that NCL levels are correlated with the abundance of proteins involved in chromosomal segregation. In conjunction with its effects on sister chromatid dynamics, NCL abrogation enhanced the anti-proliferative effects of chemical inhibitors of mitotic modulators such as the Anaphase Promoting Complex. In summary, using the AID system in combination with CRISPR/Cas9 for endogenous gene editing, our findings indicate a novel role for NCL in supporting the completion of the cell division in TNBC models, and that its abrogation could enhance the therapeutic activity of mitotic-progression inhibitors.

cancer biology↗

bioRxiv2024

An in vivo 'turning model' reveals new RanBP9 interactions in lung macrophages.

The biological functions of the scaffold protein Ran Binding Protein 9 (RanBP9) remain elusive in macrophages or any other cell type where this protein is expressed together with its CTLH (C-terminal to LisH) complex partners. We have engineered a new mouse model, named RanBP9-TurnX, where RanBP9 fused to three copies of the HA tag (RanBP9-3xHA) can be turned into RanBP9-V5 tagged upon Cre-mediated recombination. We created this model to enable stringent biochemical studies at cell type specific level throughout the entire organism. Here, we have used this tool crossed with LysM-Cre transgenic mice to identify RanBP9 interactions in lung macrophages. We show that RanBP9-V5 and RanBP9-3xHA can be both co-immunoprecipitated with the known members of the CTLH complex from the same whole lung lysates. However, more than ninety percent of the proteins pulled down by RanBP9-V5 differ from those pulled-down by RanBP9-HA. The lung RanBP9-V5 associated proteome includes previously unknown interactions with macrophage-specific proteins as well as with players of the innate immune response, DNA damage response, metabolism, and mitochondrial function. This work provides the first lung specific RanBP9-associated interactome in physiological conditions and reveals that RanBP9 and the CTLH complex could be key regulators of macrophage bioenergetics and immune functions.

cell biology↗

bioRxiv2022

Paradoxical decrease of imitation performance with age in children

AbstractWe studied the development of imitation ability in a cohort of 6-11-year-old children (N=174) with specific attention to error types and their cognitive interpretation. Participants imitated meaningless actions as if they were in front of a mirror (specularly). Actions varied across three levels of complexity (movements of a single limb, arm and leg of the same body side, or arm and leg of opposite sides). Overall performance improved with age. Among the most frequent error categories, side errors (movement imitated with the left instead of the right limb or vice-versa) paradoxically increased with age (from 9 years). Still, their sensitivity to complexity decreased with age. Thus, encoding two opposite body sides has high cognitive costs in younger children and smaller or null costs in older children. We interpreted these results in terms of the enhancement of Working Memory (WM) and body knowledge with age. When WM increases, it paradoxically drives older children to apply their superior body knowledge and imitate anatomically, producing side errors. Younger children are free from such interference because they still lack the necessary body knowledge and WM capacity. In conclusion, this study suggests that anatomical imitation becomes available in childrens cognitive repertoire from age nine due to increased body knowledge and WM capacity. Research HighlightsO_LIThe analysis of error types uncovers/illustrates the role of working memory and body knowledge in imitation. C_LIO_LIAs an effect of little working memory capacity, younger children pay a cognitive cost to encode opposite body sides and make "side errors". C_LIO_LIImitation performance improves with age, but side errors paradoxically increase in frequency due to greater ability to master body knowledge bringing to anatomical imitation. C_LIO_LIAnatomical imitation is available in childrens cognitive repertoire from age 9, as an effect of the development of body knowledge and working memory capacity. C_LI

animal behavior and cognition↗

bioRxiv2021

A novel auxin-inducible degron system for rapid, cell cycle-specific targeted proteolysis

The OsTIR1/auxin-inducible degron (AID) system allows "on demand" selective and reversible protein degradation upon exposure to the phytohormone auxin. In the current format, this technology does not allow to study the effect of acute protein depletion selectively in one phase of the cell cycle, as auxin similarly affects all the treated cells irrespectively of their proliferation status. Therefore, the AID system requires coupling with cell synchronization techniques, which can alter the basal biological status of the studied cell population. Here, we introduce a new AID system to Regulate OsTIR1 Levels based on the Cell Cycle Status (ROLECCS system), which induces proteolysis of both exogenously transfected and endogenous gene-edited targets in specific phases of the cell cycle. This new tool paves the way to studying the differential roles that target proteins may have in specific phases of the cell cycle.

synthetic biology↗

bioRxiv2020

Multisensory perception, verbal, visuo-spatial and motor working memory modulation after a single open- or closed-skill exercise session in children.

Physical activity presents clear benefits for childrens cognition; this study examined the effect of a single exercise session of open- or closed-skill exercise, as opposed to a no-exercise activity on multisensory perception, i.e. the ability to appropriately merge inputs from different sensory modalities, and on working memory (verbal, visuo-spatial, and motor working memory) in 51 preadolescent children (aged 6-8). Using a semi-randomised pre-post design, participants completed a range of cognitive tasks immediately before and after an exercise session or a classroom sedentary activity. Participants were randomised, within each school, to one of the three groups (open-skill, n=16; closed-skill, n=16; classroom activity, n=19). Exercise, but not usual classroom activity, improved childrens multisensory perception, with no difference between exercise types. Results also revealed that a single open-skill session produced verbal working memory (digit span) benefits; a closed-skill exercise session benefitted motor working memory. While the relatively small number of participants should be acknowledged as limitation, these findings contribute to emerging evidence for selective cognitive benefits of exercise, and show, for the first time in children, that multisensory processing sensitivity is improved by exercise.

animal behavior and cognition↗

bioRxiv2019

Tagging allows faithful tracing of expression and enhances biochemical detection of Ran Binding Protein 9 in vivo.

The lack of tools to reliably detect RanBP9 in vivo has significantly hampered progress in understanding the biological functions of this scaffold protein. We report here the generation of a novel mouse strain, RanBP9-TT, in which the endogenous protein is fused with a double (V5-HA) epitope tag at the C-terminus. We show that the double tag does not interfere with the essential functions of RanBP9. In contrast to RanBP9 constitutive knock-out animals, RanBP9-TT mice are viable, fertile and do not show any obvious phenotype. The V5-HA tag allows unequivocal detection of RanBP9 both by IHC and WB. Importantly, immunoprecipitation and mass spectrometry analyses reveal that the tagged protein pulls down known interactors of wild type RanBP9. Thanks to the increased detection power, we are also unveiling a novel interaction with Nucleolin, a prominent nucleolar protein. In summary, we report the generation of a new mouse line in which RanBP9 expression and interactions can be reliably studied by the use of commercially available tag antibodies. The use of this line will help to overcome some of the existing limitations in the study of RanBP9 and potentially reveal novel functions of this protein in vivo such as those linked to Nucleolin.

bioengineering↗