Biology subjects

Maiser, A.

Publications and source records attributed to Maiser, A..

4 recordsLinked to original sources

bioRxiv2025

Super-resolution compatible DNA labeling technique reveals chromatin mobility and organization changes during differentiation

Chromatin dynamics play a crucial role in cellular differentiation, yet tools for studying global chromatin mobility in living cells remain limited. Here, we developed a novel probe for the metabolic labeling of chromatin and tracking its mobility during neural differentiation. The labeling system utilizes a newly developed silicon rhodamine-conjugated deoxycytidine triphosphate (dCSiRTP). We show that this dCTP is efficiently delivered into living human induced pluripotent stem cells (iPSCs) and neural stem cells (NSCs) via a synthetic transporter (SNTT1). Using correlative confocal microscopy and stimulated emission depletion (STED) super-resolution microscopy, we quantified the sizes of labeled chromatin domains. Time lapse super-resolution microscopy combined with single particle tracking revealed that chromatin mobility decreases during the transition from iPSCs (pluripotent state) to NSCs and neurons (differentiated state). This reduction in mobility correlates with the differentiation state, suggesting a role for chromatin dynamics in cellular plasticity. Concomitant mechanistic insights obtained from MNase digestion assays, chromatin compaction and histone modification analyses revealed a decrease in chromatin accessibility during neuronal differentiation, indicating that chromatin adopts a more constrained and compacted structure. These findings provide new insights into chromatin regulation during neurogenesis.

cell biology↗

bioRxiv2025

TUB-010, a novel anti-CD30 antibody-drug conjugate based on Tub-tag technology, widens the therapeutic window by reducing toxicity while maintaining high efficacy

TUB-010 is a next-generation antibody-drug conjugate (ADC) targeting CD30, which is expressed on various hematopoietic malignancies such as Hodgkin lymphoma and anaplastic large cell lymphoma. Patients with refractory and relapsed CD30-positive cancers often lack effective and tolerable therapy options. Among the therapeutic options for these patients is brentuximab vedotin (Adcetris), a monomethyl auristatin E (MMAE)-delivering anti-CD30 ADC with a mean drug-to antibody ratio (DAR) of 4. Adcetris exhibits a high response rate at the cost of significant toxicities, among which neutropenia and peripheral neuropathy are the most prevalent adverse events, which are likely driven by the payload MMAE and instability of the maleimide conjugation chemistry. TUB-010 uses the same antibody brentuximab and payload MMAE as Adcetris, but instead of maleimide chemistry, TUB-010 is based on the Tub-tag conjugation strategy, which enables the generation of a homogenous and site-specific DAR 2 ADC with unique biophysical properties. This new technology stably attaches MMAE to the hydrophilic Tub-tag peptides on the light chains via chemoenzymatic conjugation using the enzyme tubulin tyrosine ligase. TUB-010 demonstrates similar binding affinity, internalization and lysosomal release characteristics as Adcetris in CD30-positive cells. When normalized to the MMAE concentration, TUB-010 shows comparable in vitro cytotoxic efficacy as well as similar bystander activity compared to Adcetris on established cancer cell lines. Importantly, TUB-010 exhibits higher stability with neglectable premature deconjugation in circulation and reduced high molecular weight species formation as well as lower non-specific cytotoxicity on target-negative cells compared to Adcetris. As a consequence, TUB-010 induces superior tumor control compared to Adcetris when dosed at equal MMAE concentrations in vivo and also shows lower toxicity and higher tolerability in rodents and non-human primates. Taken together, TUB-010 is a novel and potential best-in-class anti-CD30 ADC with improved biophysical properties designed to deliver the cytotoxic payload with higher precision and with a wider therapeutic window than Adcetris using Tub-tag conjugation technology. Therefore, TUB-010 may increase the clinical benefit of ADC therapies for patients with CD30-positive malignancies.

cancer biology↗

bioRxiv2019

Cohesin depleted cells pass through mitosis and reconstitute a functional nuclear architecture

Cohesin plays an essential role in chromatin loop extrusion, but its impact on a compartmentalized nuclear architecture, linked to nuclear functions, is debatable. Using live-cell and super-resolved 3D microscopy, we demonstrate that cohesin depleted cells pass through an endomitosis and rebuild a single multilobulated nucleus (MLN) with chromosome territories (CTs) pervaded by interchromatin channels. CTs contain chromatin domain clusters with a zonal organization of repressed chromatin domains in the interior and transcriptionally competent domains located at the periphery. Splicing speckles are located nearby within the lining channel system. These clusters form microscopically defined, active and inactive compartments, which correspond to A/B compartments, detected with ensemble Hi-C. Functionality of MLN despite continuous absence of cohesin was demonstrated by their ability to pass through S-phase with typical spatio-temporal patterns of replication domains. Evidence for structural changes of these domains compared to controls suggests that cohesin is required for their full integrity.

cell biology↗

bioRxiv2019

Nuclear organisation and replication timing are coupled through RIF1-PP1 interaction

Three-dimensional genome organisation and replication timing are known to be correlated, however, it remains unknown whether nuclear architecture overall plays an instructive role in the replication-timing program and, if so, how. Here we demonstrate that RIF1 is a molecular hub that co-regulates both processes. Both nuclear organisation and replication timing depend upon the interaction between RIF1 and PP1. However, whereas nuclear architecture requires the full complement of RIF1 and its interaction with PP1, replication timing is not sensitive to RIF1 dosage. RIF1s role in replication timing also extends beyond its interaction with PP1. Availing of this separation-of-function approach, we have therefore identified in RIF1 dual function the molecular bases of the co-dependency of the replication-timing program and nuclear architecture.

genomics↗