Biology subjects

Travis, C.

Publications and source records attributed to Travis, C..

4 recordsLinked to original sources

bioRxiv2026

Structure-guided targeting of the GATAD2A-CHD4 interaction within the MBD2-NuRD complex results in high levels of HbF in adult erythroid cells

Fetal hemoglobin (HbF) expression is silenced postnatally in adult erythroid cells. Sufficiently increased expression of HbF has been shown to overcome the pathophysiologic sequelae of both sickle cell disease and beta-thalassemia. As the MBD2a-NuRD chromatin remodeling complex is required for silencing of HbF, the present studies were aimed at exploring a potential therapeutic approach for disrupting this complex. AlphaFold 3 and a recent crystal structure were employed to predict the critical interaction domains linking GATAD2A in the histone deacetylase core subcomplex (HDCC) of NuRD and the CHD4 ATPase which has been shown to be required for silencing of the fetal gamma-globin (HBG) genes. The two predicted critical domains, the CR2 helical domain of GATAD2A and the C-terminal domains 1 and 2 (C1b and C2ab) of CHD4, were validated by in vitro biophysical studies. Mutation of two amino acids in the CR2 helical domain of the endogenous GATAD2A gene in HUDEP-2 cells resulted in dissociation of CHD4, loss of repressive chromatin over the HBG promoter and ~40% HbF levels compared to < 1% in control cells. Strikingly, enforced expression of a peptide containing the helical portion of the CR2 domain of GATAD2A in both HUDEP-2 cells and primary adult erythroid cells resulted in high levels of HbF, with up to ~75% HbF compared to mutant peptide control level of ~9% in the latter without perturbing erythroid differentiation. These results suggest that targeting the critical interaction domains of GATAD2A and CHD4 with a macrocyclic peptide or small molecule may lead to much needed small molecule therapeutics for sickle cell disease. Key PointsAssociation of CHD4 with the HDCC core of the MBD2-NuRD chromatin remodeling complex is required for silencing of HbF expression in adult human erythroid cells Genetic alteration or enforced peptide expression of a critical helical domain of GATAD2A results in dissociation of CHD4 from the MBD2-NuRD complex and high-level expression of HbF.

molecular biology↗

bioRxiv2026

Optogenetic Analysis of Behavior in the Mosquito Aedes aegypti

The mosquito Aedes aegypti is an important vector of viral pathogens and serves as a model for other vector species. Pathogens are transmitted when a mosquito bites a host animal, but the neural circuits that control seeking and biting behavior are not known. Here, we detail methods for the manipulation of neural activity in the mosquito using optogenetics, a key technique to determine the causal relationship between neural circuits and behavior. These methods include rearing mosquitoes for optogenetics and three assays that are designed to measure different steps in the sequence of arousal, attraction, proboscis probing, and engorgement on the blood of host animals. These behaviors occur at different spatial scales and in response to different sensory stimuli. Each behavioral assay is outfitted with red (~625 nm) LEDs for optogenetic activation. To detect arousal in response to olfactory stimuli, flight and walking are quantified. To assay attraction or landing, mosquitoes are presented with a heated blood meal in a large arena. Proboscis probing and engorgement are assayed with video resolution that enables measurement of appendages and abdomen size. The protocol describes machine vision models to enable high-resolution temporal quantification of behavior as well as endpoint measurements of feeding. These methods can be used to test the role of any genetically accessible population of neurons in mosquito biting behavior and can be extended to additional behaviors.

neuroscience↗

bioRxiv2025

Tomato pollen tube integrity is critical for pollen function at high temperature and is controlled by RALF signaling.

Reproductive success at high temperature (HT) depends on the ability of pollen to germinate a pollen tube that delivers sperm for double fertilization. We recently found that Solanum lycopersicum (tomato) cultivars capable of setting fruit at HT produce pollen tubes that continue to grow under heat stress. Our present goal is to define the molecular basis of thermotolerant pollen tube growth using quantitative live imaging, transcriptomic and proteomic profiling, and genetic analysis. We found that pollen tube integrity - the ability to maintain an intact tip during germination and elongation - was the pollen performance parameter that distinguished thermotolerant cultivars. We identified the components of the Rapid Alkalinization Factor (RALF) pollen tube integrity signal transduction pathway in tomato and found that RALF peptides repress germination at control temperature and that signaling is antagonized by HT. Loss of a single RALF peptide changes pollen tube cell wall pectin distribution and enhances pollen tube integrity at HT in thermotolerant Heinz, revealing that RALF signaling regulates thermotolerant pollen tube growth and establishing a molecular framework for improving reproductive heat-resilience in crop plants.

plant biology↗

bioRxiv2022

helixCAM: A Platform for Programmable Cellular Assembly in Bacteria and Human Cells

Interactions between cells are indispensable for creating structure and signaling. The ability to direct precise cell-cell interactions would be powerful for engineering tissues, understanding signaling pathways, and directing immune cell targeting. In humans, intercellular interactions are mediated by cell adhesion molecules (CAMs). However, CAMs are natively expressed by many cells and have cross-reactivity, making them unsuitable for programming specific interactions. Here, we showcase "helixCAM," a platform for engineering novel CAMs by presenting coiled-coil peptides on the cell surface. helixCAMs were able to create specific cell-cell interactions and direct patterned aggregate formation in bacteria and human cells. We built rationally designed helixCAM libraries and discovered novel high-performance helixCAM pairs. High-affinity helixCAMs were then used for multicellular engineering applications, such as spherical layering, adherent cell targeting, and surface patterning. The helixCAMs are an expandable platform for directing complex multicellular assemblies, and we foresee its utility in tissue engineering, immunology, and developmental biology.

synthetic biology↗