Biology subjects

DelRosso, N. V.

Publications and source records attributed to DelRosso, N. V..

4 recordsLinked to original sources

bioRxiv2025

Bifunctional transcriptional effector domains control gene expression pulses in an occupancy-dependent manner

Dynamic gene expression pulses enable adaptive response to stimuli and can be generated in natural and synthetic systems. Controlling these dynamics typically involves circuits consisting of multiple genes and transcription factors (TFs). Here, we discover a new class of bifunctional transcriptional effector domains that can first activate and subsequently repress the same gene, producing dynamic gene expression pulses from a single input. These pulse dynamics arise from distinct, temporally separated chromatin states defined by active and repressive chromatin modifications. The balance between active and repressed states is determined by the DNA occupancy of the bifunctional TF. Bifunctional domains activate at low occupancy but switch to repression at high occupancy, resulting in a non-monotonic TF input-gene expression output relationship tunable by TF concentration and number of DNA binding sites. We develop a kinetic model that links TF occupancy to gene expression transitions, allowing for the programming of eight distinct cell "states" - combinations of On/Off states of 3 reporter genes - using a single bifunctional effector. This work establishes the theoretical framework and molecular mechanisms of pulse-generating gene regulation by bifunctional domains and creates a foundation for engineering complex multi-gene circuits.

systems biology↗

bioRxiv2025

ADAPT-M: A workflow for rapid, quantitative in vitro measurements of enriched protein libraries

Protein-protein interactions underpin most cellular interactions, and engineered binders present powerful tools for probing biology and developing novel therapeutics. One bottleneck in binder generation is the scalable, quantitative characterization of these interactions. We present ADAPT-M (Affinity Determination by Adaptation of ProTein binders for Microfluidics), a streamlined workflow that connects yeast surface display (YSD) with in vitro affinity and kinetic measurements using the high-throughput STAMMPPING microfluidic platform. ADAPT-M quantifies Kds and dissociation kinetic parameters for hundreds of enriched protein variants in under one week without requiring hands-on protein purification. We applied ADAPT-M to a computationally designed library targeting the SARS-CoV-2 Omicron BA.1 receptor binding domain, successfully recovering and measuring Kds for most highly enriched YSD variants. Measurements correlate strongly with biolayer interferometry and yeast titration assays. ADAPT-M further enabled selection of lead candidates for structural and mutational analysis, which revealed designed paratopes were preserved despite binding to off-target epitopes. By bridging YSD screening and in vitro validation, ADAPT-M accelerates protein binder discovery and supports data-driven protein engineering.

biophysics↗

bioRxiv2020

High-throughput binding affinity measurements for mutations spanning a transcription factor-DNA interface reveal affinity and specificity determinants

Transcription factors (TFs) bind regulatory DNA to control gene expression, and mutations to either TFs or DNA can alter binding affinities to rewire regulatory networks and drive phenotypic variation. While studies have profiled energetic effects of DNA mutations extensively, we lack similar information for TF variants. Here, we present STAMMP (Simultaneous Transcription Factor Affinity Measurements via Microfluidic Protein Arrays), a high-throughput microfluidic platform enabling quantitative characterization of hundreds of TF variants simultaneously. Measured affinities for [~]210 mutants of a model yeast TF (Pho4) interacting with 9 oligonucleotides (>1,800 Kds) reveal that many combinations of mutations to poorly conserved TF residues and nucleotides flanking the core binding site alter but preserve physiological binding, providing a mechanism for mutations in cis and trans to rewire networks without insurmountable evolutionary penalties. Moreover, biochemical double-mutant cycles across the TF-DNA interface reveal molecular mechanisms driving recognition, linking sequence to function.

biophysics↗

bioRxiv2018

An event-based paradigm for analyzing fluorescent astrocyte activity uncovers novel single-cell and population-level physiology

Recent work examining astrocytic physiology centers on fluorescence imaging approaches, due to development of sensitive fluorescent indicators and observation of spatiotemporally complex calcium and glutamate activity. However, the field remains hindered in fully characterizing these dynamics, both within single cells and at the population-level, because of the insufficiency of current region-of-interest-based approaches to describe activity that is often spatially unfixed, size-varying, and propagative. Here, we present a paradigm-shifting analytical framework that releases astrocyte biologists from ROI-based tools. Astrocyte Quantitative Analysis (AQuA) software enables users to take an event-based approach to accurately capture and quantify the irregular activity observed in astrocyte imaging datasets. We apply AQuA to a range of ex vivo and in vivo imaging data, and uncover previously undescribed physiological phenomena in each. Since AQuA is data-driven and based on machine learning principles, it can be applied across model organisms, fluorescent indicators, experimental modes, and imaging resolutions and speeds, enabling researchers to elucidate fundamental astrocyte physiology.

neuroscience↗