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Biology subjects

Gergely, F.

Publications and source records attributed to Gergely, F..

4 recordsLinked to original sources

Human Choroid Plexus Organoids Progress to Postnatal-like Maturation and Reveal a Closing Window of Developmental Plasticity

The choroid plexus (ChP) produces cerebrospinal fluid (CSF) and forms the blood-CSF barrier, yet the developmental programme driving its maturation in humans remains poorly understood. Using a 15-timepoint single-cell RNA sequencing atlas of human ChP organoids benchmarked against human tissue, we resolve an ordered differentiation process comprising cell cycle exit, ciliogenesis and ion transporter expression. Maturation culminates in a transcriptional state with features of human adult ChP, establishing the first in vitro ChP model to reach postnatal-like milestones. Centrosome proteomics identified previously uncharacterised, stage-specific regulators of ciliogenesis. To probe developmental plasticity, we perturbed ChP organoids with valproic acid (VPA), a clinically used antiepileptic and established teratogen. Early VPA-mediated disruption of multiciliogenesis and secretion recovered upon drug withdrawal, whereas late treatment washout resulted in persistent impairment of mature transporters. Together, these findings resolve the developmental programme by which the ChP reaches functionally mature identity and identify a stage-dependent plasticity window during its maturation.

developmental biology↗

Selective miniprotein inhibitors of Aurora-A kinase designed using interaction-motif scaffolding

Targeting kinase ATP-binding sites has produced many successful therapeutics, but selectivity remains a major challenge. We hypothesised that substrate-recognition surfaces could provide an alternative route to selective kinase inhibition. Here, we designed and tested structure-guided miniprotein inhibitors of Aurora-A using N-Myc as a template, a natural weak binder of the P+1 pocket. The most potent designs bind Aurora-A with single-digit nanomolar affinity, more than a thousand fold higher than the starting template, and selectively inhibit Aurora-A over Aurora-B in kinase assays and mitotic cells. Despite diverse architectures, successful binders targeting the substrate-recognition surface converged on a common strategy, coupling extensive engagement of the G helix with activation loop stabilisation. Together these results show that selective kinase inhibition can be achieved by exploiting structurally well-defined active-state conformations rather than kinase-specific inactive states. Our work establishes a framework for converting weak substrate-recognition surface interactors into potent, selective kinase inhibitors through structure-guided protein design.

molecular biology↗

A high-content RNAi screen reveals multiple roles for long noncoding RNAs in cell division

Genome stability relies on proper coordination of mitosis and cytokinesis, where dynamic microtubules capture and faithfully segregate chromosomes into daughter cells. The role of long noncoding RNAs (lncRNAs) in controlling these processes however remains largely unexplored. To identify lncRNAs with mitotic functions, we performed a high-content RNAi imaging screen targeting more than 2,000 human lncRNAs. By investigating major hallmarks of cell division such as chromosome segregation, mitotic duration and cytokinesis, we discovered numerous lncRNAs with functions in each of these processes. The chromatin-associated lncRNA, linc00899, was selected for in-depth studies due to the robust mitotic delay observed upon its depletion. Transcriptome analysis of linc00899-depleted cells together with gain-of-function and rescue experiments across multiple cell types identified the neuronal microtubule-binding protein, TPPP/p25, as a target of linc00899. Linc00899 binds the genomic locus of TPPP/p25 and suppresses its transcription through a cis-acting mechanism. In cells depleted of linc00899, the consequent upregulation of TPPP/p25 alters microtubule dynamics and is necessary and sufficient to delay mitosis. Overall, our comprehensive screen identified several lncRNAs with roles in genome stability and revealed a new lncRNA that controls microtubule behaviour with functional implications beyond cell division.

cell biology↗

Specificity of RNAi, LNA and CRISPRi as loss-of-function methods in transcriptional analysis

Loss-of-function (LOF) methods, such as RNA interference (RNAi), antisense oligonucleotides or CRISPR-based genome editing, provide unparalleled power for studying the biological function of genes of interest. When coupled with transcriptomic analyses, LOF methods allow researchers to dissect networks of transcriptional regulation. However, a major concern is nonspecific targeting, which involves depletion of transcripts other than those intended. The off-target effects of each of these common LOF methods have yet to be compared at the whole-transcriptome level. Here, we systematically and experimentally compared non-specific activity of RNAi, antisense oligonucleotides and CRISPR interference (CRISPRi). All three methods yielded non-negligible offtarget effects in gene expression, with CRISPRi exhibiting clonal variation in the transcriptional profile. As an illustrative example, we evaluated the performance of each method for deciphering the role of a long noncoding RNA (lncRNA) with unknown function. Although all LOF methods reduced expression of the candidate lncRNA, each method yielded different sets of differentially expressed genes upon knockdown as well as a different cellular phenotype. Therefore, to definitively confirm the functional role of a transcriptional regulator, we recommend the simultaneous use of at least two different LOF methods and the inclusion of multiple, specifically designed negative controls.

genomics↗