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Abstract The Notch receptor is a pleiotropic signaling protein that translates intercellular ligand interactions into changes in gene expression via the nuclear localization of the Notch intracellular Domain (NICD). Using a combination of immunohistochemistry, RNA in situ, Optogenetics and super-resolution live imaging of transcription in human cells, we show that the N1ICD can form condensates that positively facilitate Notch target gene expression. We determined that N1ICD undergoes Phase Separation Coupled Percolation (PSCP) into transcriptional condensates, which recruit, enrich, and encapsulate a broad set of core transcriptional proteins. We show that the capacity for condensation is due to the intrinsically disordered transcriptional activation domain of the N1ICD. In addition, the formation of such transcriptional condensates acts to promote Notch-mediated super enhancer-looping and concomitant activation of the MYC protooncogene expression. Overall, we introduce a novel mechanism of Notch1 activity in which discrete changes in nuclear N1ICD abundance are translated into the assembly of transcriptional condensates that facilitate gene expression by enriching essential transcriptional machineries at target genomic loci.

One form of Indonesian cultural wisdom is the use of leaves as food packaging. In addition to being used as a packaging material, patat leaves are also believed to have antidiabetic benefits. Antidiabetic activity can be assessed through the enzyme α-glucosidase inhibitory activities. In this research, an in vitro and in silico analysis of antidiabetic activity was conducted for the first time on nonpolar extracts of patat leaves. In vitro analysis was conducted using the α-glucosidase enzyme inhibition method, compound analysis was conducted using GC‒MS/MS, and an in silico study was conducted via the molecular docking method to the α-glucosidase receptor (PDB: 3W37). The results showed that the nonpolar extract (n-hexane) had very weak antidiabetic activity (with an IC50 >> 100 ppm). However, the sample inhibited α-glucosidase enzyme activity by up to 86.91%. GC‒MS/MS analysis confirmed the presence of 19 compounds in the nonpolar extract of the patat leaves. Straight-chain hydrocarbons dominate the compounds. The compound with the greatest abundance was Octadecyl 2,2,2-trifluoroacetate (RT 33.908; 9.53% area). An in silico test revealed that the compound with the greatest potential as an antidiabetic agent was γ-methylionone (40.78 μM). On the basis of the results of this theoretical approach, the compound can be further analyzed to validate its activity.

With advancements in multicomponent molecular biological tools, the need for versatile, rapid and cost-effective cloning that enables successful combinatorial assembly of DNA plasmids of interest is becoming increasingly important. Unfortunately, current cloning platforms fall short regarding affordability, ease of combinatorial assembly and, above all, the ability to iteratively remove individual cassettes at will. Herein we construct, implement and make available a broad set of cloning vectors, called PlayBack vectors, that allow for the expression of several different constructs simultaneously under separate promoters. Overall, this system is substantially cheaper than other multicomponent cloning systems, has usability for a wide breadth of experimental paradigms and includes the novel feature of being able to selectively remove components of interest at will at any stage of the cloning platform.

Drosophila melanogaster has been used as a model system to identify and characterize genetic contributions to development, homeostasis, and to investigate the molecular determinants of numerous human diseases. While there exist many differences at the genetic, structural, and molecular level, many signalling components and cellular machineries are conserved between Drosophila and humans. For this reason, Drosophila can and has been used extensively to model, and study human pathologies. The extensive genetic resources available make this model system a powerful one. Over the years, the sophisticated and rapidly expanding Drosophila genetic toolkit has provided valuable novel insights into the contribution of genetic components to human diseases. The activity of Notch signalling is crucial during development and conserved across the Metazoa and has been associated with many human diseases. Here we highlight examples of mechanisms involving Notch signalling that have been elucidated from modelling human diseases in Drosophila melanogaster that include neurodegenerative diseases, congenital diseases, several cancers, and cardiac disorders.

Retinoic acid, the active metabolite of Vitamin A, is important for the appropriate development of the nervous system (e.g., neurite outgrowth) as well as for cognition (e.g., memory formation) in the adult brain. We have shown that many of the effects of retinoids are conserved in the CNS of the mollusc, Lymnaea stagnalis. RXRs are predominantly nuclear receptors, but the Lymnaea RXR (LymRXR) exhibits a non-nuclear distribution in the adult CNS, where it is also implicated in non-genomic retinoid functions. As such, we developed a CNS Drosophila organ culture-based system to examine the transcriptional activity and ligand-binding properties of LymRXR, in the context of a live invertebrate nervous system. The novel ligand sensor system was capable of reporting both the expression and transcriptional activity of the sensor. Our results indicate that the LymRXR ligand sensor mediated transcription following activation by both 9-cis RA (the high affinity ligand for vertebrate RXRs) as well as the vertebrate RXR synthetic agonist, SR11237. The LymRXR ligand sensor was also activated by all-trans RA, and to a much lesser extent by the vertebrate RAR synthetic agonist, EC23. This sensor also detected endogenous retinoid-like activity in the CNS of developing Drosophila larvae, primarily during the 3rd instar larval stage. These data indicate that the LymRXR sensor can be utilized not only for characterization of ligand activation for studies related to the Lymnaea CNS, but also for future studies of retinoids and their functions in Drosophila development.

A letter to the editor is presented in response to the article "Levels of Physician Involvement with Patients and their Families: A Model for Teaching and Research," by M. K. Marvel and colleagues in the December 1994 issue of the "Journal of Family Practice."

A response by M. Kim Marvel and colleagues to a letter to the editor about their article "Levels of Physician Involvement with Patients and their Families: A Model for Teaching and Research" in the December 1994 issue is presented.

The Notch receptor is a pleiotropic signaling protein that translates intercellular ligand interactions into changes in gene expression via the nuclear localization of the Notch intracellular Domain (NICD). Using a combination of immunohistochemistry, RNA in situ, Optogenetics and super-resolution live imaging of transcription in human cells, we show that the N1ICD can form condensates that positively facilitate Notch target gene expression. We determined that N1ICD undergoes Phase Separation Coupled Percolation (PSCP) into transcriptional condensates, which recruit, enrich, and encapsulate a broad set of core transcriptional proteins. We show that the capacity for condensation is due to the intrinsically disordered transcriptional activation domain of the N1ICD. In addition, the formation of such transcriptional condensates acts to promote Notch-mediated super enhancer-looping and concomitant activation of the MYC protooncogene expression. Overall, we introduce a novel mechanism of Notch1 activity in which discrete changes in nuclear N1ICD abundance are translated into the assembly of transcriptional condensates that facilitate gene expression by enriching essential transcriptional machineries at target genomic loci., (© 2024. Crown.)

Lymph nodes and other secondary lymphoid organs play critical roles in immune surveillance and immune activation in mammals, but the deep internal locations of these organs make it challenging to image and study them in living animals. Here, we describe a previously uncharacterized external immune organ in the zebrafish ideally suited for studying immune cell dynamics in vivo , the axillary lymphoid organ (ALO). This small, translucent organ has an outer cortex teeming with immune cells, an inner medulla with a mesh-like network of fibroblastic reticular cells along which immune cells migrate, and a network of lymphatic vessels draining to a large adjacent lymph sac. Noninvasive high-resolution imaging of transgenically marked immune cells can be carried out in the lobes of living animals, and the ALO is readily accessible to external treatment. This newly discovered tissue provides a superb model for dynamic live imaging of immune cells and their interaction with pathogens and surrounding tissues, including blood and lymphatic vessels., Competing Interests: Competing interests: Authors declare that they have no competing interests.