Biology subjects

Dominguez, D.

Publications and source records attributed to Dominguez, D..

At least 19 recordsLinked to original sources

bioRxiv2026

Robust mammalian RNA localization elements are complex and multipartite

The subcellular localization patterns of RNAs are controlled by regulatory elements contained within them. However, for most localized RNAs, the identities of these elements remain unknown. We had previously identified several localization elements that are necessary and sufficient for robust, kinesin-dependent RNA targeting to microtubule plus ends in a variety of cell types. Yet the characteristics of these elements that are critical for function remained unclear. To address this, we systematically created tens of thousands of mutant localization elements and quantified their ability to regulate subcellular RNA localization in neuronal cells. We found that the minimally active size of these localization elements is large, approximately 200 nucleotides. These elements contain multiple important subsequences, with some being completely intolerant of any changes and others being tolerant to a shuffling of nucleotide order but not to changes in nucleotide composition. Using single molecule microscopy, we verified these findings in primary rat neurons. Together, these results demonstrate that highly active mammalian RNA localization elements are large, complex, and multipartite and lay a foundation for further mechanistic studies of their function.

molecular biology↗

bioRxiv2026

Overgrazing drives ant diversity loss and community homogenization in the Tumbesian dry forest in Ecuador

Tropical dry forests are among the worlds most threatened ecosystems, having lost over 60% of their original extent due to agricultural expansion and livestock grazing. Despite a growing body of research on the effects of deforestation and habitat fragmentation, the consequences of overgrazing on ant communities remain poorly documented, particularly in the Tumbesian bioregion, where uncontrolled goat grazing continues to be the primary disturbance with detrimental effects to plant communities and all the life they support. We sampled ant communities across a goat grazing gradient in a Tumbesian dry forest in Loja, Ecuador. Nine sampling clusters were distributed across a 20 x 25 km landscape on three levels of grazing degradation (low, moderate, and high). Within each cluster, we established three 60 x 60 m plots separated by at least 250 m from each other. Eighteen pitfall traps were deployed per plot. Ant community responses to goat grazing were assessed using abundance- and incidence-based analyses and quantified vegetation structure with satellite-derived NDVI. We collected 47,473 individuals (abundance) in 1,871 collection events (incidence) representing 22 species in six ant subfamilies. Species richness declined with grazing degradation (low = 20 spp.; moderate = 15; high = 13), and generalist forager species dominated the more degraded landscape. Beta diversity decomposition revealed a shift from turnover-dominated dissimilarity at the low moderate degradation transition to nestedness-dominated dissimilarity at the moderate high transition, indicating increasing habitat simplification with higher land degradation. While changes in community composition showed a non-significant trend along the land degradation gradient, our trait-based analysis evidenced effects on the functional space occupied by ants: under High degradation level intensity, ants became smaller, smoother and darker. These findings underscore the conservation value of pristine and low degradation forests and support grazing exclusion as a precautionary component of restoration strategies.

ecology↗

bioRxiv2026

Sequence and structure of protein binding sites in RNA impact biomolecular condensates

Biomolecular condensates are central to subcellular compartmentalization. Although many condensates contain and regulate RNA, research has primarily focused on protein interactions. Here, we investigate RNA-protein interactions underlying cell cycle-regulating condensates in the multinucleate fungus Ashbya gossypii. These condensates form through interactions between G1 cyclin mRNA CLN3 and RNA-binding protein Whi3, which was predicted by homology to recognize a five-nucleotide motif repeated within the transcript. Natural variation in motif number in Ashbya strains led us to hypothesize that binding site valence may influence condensate properties. Using unbiased binding assays, we determined the preference of Ashbya Whi3 protein for specific primary RNA sequence and mutated individual Whi3-binding sites within CLN3 mRNA. Mutants exhibited distinct condensate properties despite having the same valence in terms of binding site number. Mutations altered the saturation concentration (Csat) and dense phase concentration of RNA and protein in cell-free reconstitution experiments. A subset of mutants, showed reduced number of condensates and deregulation of the cell cycle in cells. We also find that enhanced availability of single-stranded RNA can compensate for loss of binding sites. Together, these data indicate that differences in RNA protein binding-site context and not simply valence plays a critical role in determining condensate properties.

cell biology↗

bioRxiv2025

Charting the Multi-level Molecular Response to Palbociclib in ER-Positive Breast Cancer

The addition of CDK4/6 inhibitors to endocrine therapy has significantly improved outcomes in HR+/HER2-breast cancer. However, variable patient responses and acquired resistance remain a clinical challenge. We therefore defined the comprehensive molecular response to palbociclib, the most clinically used CDK4/6 inhibitor. Global analyses of gene expression, protein abundance, splicing, and chromatin accessibility revealed broad patterns and specific changes that result from CDK4/6-inhibition in breast cancer cells. We uncovered unexpected feedback between CDK4/6 and estrogen-response signaling, which has clear clinical implications. We also revealed a widespread alternative splicing program that partially overlapped with genes whose expression is regulated, and which is expected to impact protein function. These molecular changes nominated combination therapies that interfere with the activation of CDKs or ER. Accordingly, co-targeting CDK7, which regulates CDK2, CDK4/6 and ER, additively impacted cell fitness. Collectively, these data reveal a complex, multi-tiered response to CDK4/6 inhibition, with implications for therapeutic efficacy.

molecular biology↗

bioRxiv2025

The role of the L421P mutation in Penicillin-Binding Protein 1 (PBP1) in the evolution of chromosomally mediated penicillin resistance in Neisseria gonorrhoeae

ponAL421P encodes a mutated variant of penicillin-binding protein 1 (PBP1) and is a key resistance determinant that increases the penicillin MIC (MICPEN) above the clinical breakpoint in Neisseria gonorrhoeae. Despite the removal of penicillin from treatment guidelines for gonococcal infections in the 1980s, ponAL421P is present in nearly 50% of current N. gonorrhoeae isolates in the PubMLST database. Bioinformatic analysis indicates that ponAL421P is exclusive to N. gonorrhoeae isolates, whereas Leu-421 is 100% conserved in other Neisseria species. To understand the involvement of ponAL421P in antibiotic resistance, we introduced ponA variants encoding 16 different amino acids at position-421 into FA6140, a penicillin-resistant gonococcal isolate that naturally harbors ponAL421P. Proline-421 was the only mutation that increased the MICPEN to the same level as FA6140. We also assessed the fitness of strains with the 16 mutant ponA alleles over multiple serial passages, both with and without sub-MIC levels of penicillin. There was no fitness defect attributed to ponAL421P under these experimental conditions; instead, our analyses suggest that the widespread occurrence of ponAL421P is driven by its capacity to increase the MICpen above the clinical breakpoint. In FA6140 transformed with the mosaic penA allele from strain H041, a ceftriaxone-resistant isolate, ponAL421P increased the MIC of ceftriaxone, suggesting that ceftriaxone targets PBP1 in this strain. We conclude that the ponAL421P allele emerged in gonococcal isolates, increasing the MICPEN above the clinical breakpoint, and has remained in the population even after the removal of penicillin from treatment guidelines. ImportanceThe emergence of antibiotic-resistant Neisseria gonorrhoeae threatens effective treatment of gonorrhea, one of the most common sexually transmitted infections worldwide. Understanding the genetic changes that drive and maintain resistance is crucial for anticipating future resistance trends. Here, we investigated the impact of a key resistance mutation in PBP1 (encoded by ponAL421P). Although penicillin has not been used to treat gonorrhea for decades, this mutation remains widespread even in recent N. gonorrhoeae isolates. ponAL421P confers clinically relevant penicillin resistance without imposing an in vitro fitness cost. ponAL421P also increases resistance to ceftriaxone in strains with penA alleles that are associated with ceftriaxone resistance. This work highlights the role of the ponAL421P allele in shaping the current antibiotic resistance landscape and supports the need for ongoing surveillance and evolutionary studies of such mutations in the gonococcal population.

microbiology↗

bioRxiv2025

Xist Repeat A coordinates an assembly of SR proteins to recruit SPEN and induce gene silencing

The lncRNA Xist represents a paradigm to understand the mechanisms of RNA-mediated gene silencing in mammals, which remain largely unresolved. To induce silencing, Xist recruits the RNA-binding protein SPEN through its 5'-proximal Repeat A domain. Yet, how Repeat A recruits SPEN and how SPEN coordinates silencing remain unclear. We report that sequences in Repeat A critical for SPEN recruitment directly bind SR-rich splicing factors. SRSF1, one such factor, is required for optimal SPEN recruitment and its RS-domain recruits SPEN when tethered to Xist. SPEN and SR-protein-binding motifs promote Repeat As association with many proteins, including the m6A machinery and elongating RNA polymerase II. SPEN also represses autosomal genes where its recruitment coincides with SR-protein binding. Our results reveal an unexpectedly essential role for splicing factors in coordinating silencing by Xist and suggest that the sensing of SR-protein-rich assemblies is a general mechanism through which SPEN targets genes for repression.

genetics↗

bioRxiv2025

Contributions of Folded and Disordered Domains to RNA Binding by HNRNPR

RNA binding proteins (RBPs) interact with and tightly regulate the fate of messenger RNAs but how RNA targets are recognized remains a challenging question. RBPs often contain multiple domains known to directly bind RNA, such as RNA recognition motifs (RRMs), as well as domains whose RNA binding capacity remains incompletely understood, e.g., low complexity domains (LCDs). Here, we dissect HNRNPR, an RBP with three RRMs and an arginine-glycine rich (RG-rich) LCD. We apply unbiased high-throughput biochemical approaches and identify critical RNA binding domains that confer specificity. We show that not all RRMs contribute equally to binding and find that RRM3, along with a downstream C-terminal charged region, are required for RNA binding. We find that HNRNPR also binds RNA G-quadruplexes (rG4s) and map multiple rG4 binding sites including RRM3 with the C-terminal charged region and RG-rich regions within the LCD. We dissect rG4 specificity for the full length HNRNPR and LCD using a newly created RNA pool focused on rG4s and reveal that binding is dependent on RNA folding and find specific rG4 features that enhance HNRNPR-rG4 interactions. Our work highlights the complexity of RBP-RNA interactions and motivates the study of disordered regions as RNA binding domains.

biochemistry↗

bioRxiv2025

Massively parallel characterization of RNA G-quadruplex stability and molecular recognition

RNA G-quadruplexes (rG4s) have been implicated as important regulators of RNA metabolism and are promising targets for RNA-targeted therapeutics. rG4s typically require a canonical (G[≥]2N1-7)4 motif, but the sequence features that affect rG4 stability and recognition by RNA-binding proteins (RBPs) and rG4-binding ligands are not fully understood. To interrogate sequence-level drivers of rG4 folding, we applied a reverse-transcriptase stop sequencing strategy to a library of [~]3,000 synthetic rG4s with varied G-tract lengths, loop lengths, and loop compositions, permitting massively parallel quantification of rG4 stability. Our data confirm known sequence-level features and characterize novel combinatorial impacts of these features. We also assessed systematically mutagenized natural rG4s, revealing unexpected mutations that significantly affect rG4 stability, including contributions from flanking sequences outside of the rG4. We further used our strategy to assess rG4 recognition preferences of the model rG4- ligand pyridostatin, revealing a preferential stabilization of rG4s containing mixed-length G-tracts. We further demonstrated the potential for large-scale protein binding assays with our library to reveal rG4 features recognized by RBPs, specifically G3BP1 and FMRP. Our approach and data provide a generalizable framework to study sequence-level drivers of rG4 stability, binding by RBPs, and ligand interactions, defining basic principles of rG4 formation and downstream biology.

biochemistry↗

bioRxiv2025

TDP-43 directly inhibits RNA accumulation in neurites through modulation of RNA stability

The subcellular localization of hundreds of RNAs to neuronal projections allows neurons to efficiently and rapidly react to spatially restricted external cues. However, for the vast majority of these RNAs, the mechanisms that govern their localization are unknown. Here we demonstrate that the ALS-associated RNA binding protein TDP-43 primarily acts to keep RNAs out of neuronal projections. Using subcellular fractionation and single molecule RNA FISH we find that TDP-43 loss results in the increased neurite accumulation of hundreds of RNAs. These RNAs are highly enriched for known TDP-43 binding sites, suggesting that TDP-43 directly binds them to regulate their localization. We then identified precise regions within RNAs that mediate their TDP-43-dependent localization and interaction with TDP-43 using high-throughput functional assays in cells and high-throughput binding assays in vitro. We found that these regions also mediated TDP-43-dependent RNA instability, identifying the mechanism by which TDP-43 regulates RNA localization. ALS-associated mutations in TDP-43 resulted in similar RNA mislocalization phenotypes as did TDP-43 loss in human iPS-derived motor neurons. These findings establish TDP-43 as a direct negative regulator of RNA abundance in neurites and suggest that mislocalization of specific transcripts may occur in ALS patients.

molecular biology↗

bioRxiv2025

Heterochromatin fidelity is a therapeutic vulnerability in lymphoma and other human cancers

Genes involved in the regulation of chromatin structure are frequently disrupted in cancer, contributing to an aberrant transcriptome and phenotypic plasticity. Yet, therapeutics targeting mutant forms of chromatin-modifying enzymes have yielded only modest clinical utility, underscoring the difficulty of targeting the epigenomic underpinnings of aberrant gene regulatory networks. Here, we sought to identify novel epigenetic vulnerabilities in diffuse large B-cell lymphoma (DLBCL). Through phenotypic screens and biochemical analysis, we demonstrated that inhibition of the H3K9 demethylases KDM4A and KDM4C elicits potent, subtype-agnostic cytotoxicity by antagonizing transcriptional networks associated with B-cell identity and epigenetically rewiring heterochromatin. KDM4 demethylases associated with the KRAB zinc finger ZNF587, and their enzymatic inhibition led to DNA replication stress and DNA damage-induced cGAS-STING activation. Broad surveys of transcriptional data from patients also revealed KDM4 family dysregulation in several other cancer types. To explore this potential therapeutic avenue, we performed high-throughput small molecule screens with H3K9me3 nucleosome substrates and identified novel KDM4 demethylase inhibitors. AI-guided protein-ligand binding predictions suggested diverse modes of action for various small molecule hits. Our findings underscore the relevance of targeting fundamental transcriptional and epigenetic mechanisms for anti-cancer therapy. HIGHLIGHTSO_LIPhenotypic screens identified JIB-04 as a potent anti-cancer agent for multiple subtypes of diffuse large B-cell lymphoma C_LIO_LIJIB-04 binds and inhibits KDM4 demethylases resulting in epigenomic rewiring of heterochromatin C_LIO_LIKDM4 demethylases cooperate with KRAB zinc fingers to limit DNA replication stress, and KDM4 inhibition instigates DNA-damage and cGAS-STING activation in several human cancers C_LIO_LIHigh-throughput small molecule screens with semi-synthetic nucleosome substrates and AI-guided molecular docking simulations identify novel KDM4 inhibitors C_LI

genomics↗

bioRxiv2024

Dissecting RNA Selectivity Mediated by Tandem RNA-Binding Domains

RNA-protein interactions are pivotal to proper gene regulation. Many RNA-binding proteins possess multiple RNA-binding domains; however, how these domains interplay to specify and regulate RNA targets remains poorly understood. Here, we investigate three multi-domain proteins, Musashi-1, Musashi-2, and Unkempt, three factors which share a high degree of RNA specificity. We use a combination of massively parallel in vitro assays with random or naturally derived RNA sequences and find that individual domains within a protein can have differing affinities, specificities, and spacing preferences. Further, we emphasize that while all three proteins have overlapping motif specificities, non-overlapping sequences may allow for target discrimination. We carry out large scale competition assays between these proteins and determine how individual protein specificities and affinities influence competitive binding. Integration of in vivo binding and regulation with in vitro specificities shows that target selection involves a combination of the protein intrinsic specificities described here, but cellular context is critical to drive these proteins to motifs in specific transcript regions. Finally, evolutionarily conserved RNA regions display evidence of binding multiple RBPs in vivo, and these RNA regions recapitulate this trend with the highest affinity in vitro. We highlight the importance of understanding features of complex RNA-protein interactions and how protein-target discrimination can be established.

biochemistry↗

bioRxiv2024

Iron-sensitive RNA regulation by poly C binding proteins

Iron is essential for normal cellular function. Homeostatic responses to low iron availability have long been known to rely on posttranscriptional mechanisms. Poly C binding proteins (PCBPs) are essential RNA binding proteins that regulate alternative splicing, translation and RNA stability. They also serve as critical iron chaperones that manage intracellular iron flux. However, the impact of cellular iron levels on the PCBP-directed transcriptome has not been globally evaluated. We have found broad transcriptome changes in response to low iron availability consistent with numerous operant posttranscriptional mechanisms that sense iron. By comparing gene expression and alternative splicing directed by PCBPs to the iron-sensitive transcriptome, we found genes with iron-sensitive PCBP RNA regulation. Further, we demonstrate that cellular iron levels impact PCBP1 RNA binding. Our data show a large-scale RNA regulatory response to cellular iron levels and open the possibility for other iron-sensitive RNA binding proteins.

molecular biology↗

bioRxiv2024

G4mer: An RNA language model for transcriptome-wide identification of G-quadruplexes and disease variants from population-scale genetic data

RNA G-quadruplexes (rG4s) are key regulatory elements in gene expression, yet the effects of genetic variants on rG4 formation remain underexplored. Here, we introduce G4mer, an RNA language model that predicts rG4 formation and evaluates the effects of genetic variants across the transcriptome. G4mer significantly improves accuracy over existing methods, highlighting sequence length and flanking motifs as important rG4 features. Applying G4mer to 5 untranslated region (UTR) variations, we identify variants in breast cancer-associated genes that alter rG4 formation and validate their impact on structure and gene expression. These results demonstrate the potential of integrating computational models with experimental approaches to study rG4 function, especially in diseases where non-coding variants are often overlooked. To support broader applications, G4mer is available as both a web tool and a downloadable model.

genetics↗

bioRxiv2024

Understanding species-specific and conserved RNA-protein interactions in vivo and in vitro

While evolution is often considered from a DNA- and protein-centric view, RNA-based regulation can also impact gene expression and protein sequences. Here we examined interspecies differences in RNA-protein interactions using the conserved neuronal RNA binding protein, Unkempt (UNK) as model. We find that roughly half of mRNAs bound in human are also bound in mouse. Unexpectedly, even when transcript-level binding was conserved across species differential motif usage was prevalent. To understand the biochemical basis of UNK-RNA interactions, we reconstituted the human and mouse UNK-RNA interactomes using a high-throughput biochemical assay. We uncover detailed features driving binding, show that in vivo patterns are captured in vitro, find that highly conserved sites are the strongest bound, and associate binding strength with downstream regulation. Furthermore, subtle sequence differences surrounding motifs are key determinants of species-specific binding. We highlight the complex features driving protein-RNA interactions and how these evolve to confer species-specific regulation.

evolutionary biology↗

bioRxiv2023

Methylation of histone H3 lysine 36 is a barrier for therapeutic interventions of head and neck squamous cell carcinoma.

Approximately 20% of head and neck squamous cell carcinomas (HNSCC) exhibit reduced methylation on lysine 36 of histone H3 (H3K36me) due to mutations in histone methylase NSD1 or a lysine-to-methionine mutation in histone H3 (H3K36M). Whether such alterations of H3K36me can be exploited for therapeutic interventions is still unknown. Here, we show that HNSCC models expressing H3K36M can be divided into two groups: those that display aberrant accumulation of H3K27me3 and those that maintain steady levels of H3K27me3. The first group shows decreased proliferation, genome instability, and increased sensitivity to genotoxic agents, such as PARP1/2 inhibitors. In contrast, the H3K36M HNSCC models with steady H3K27me3 levels do not exhibit these characteristics unless H3K27me3 levels are elevated, either by DNA hypomethylating agents or by inhibiting the H3K27me3 demethylases KDM6A/B. Mechanistically, we found that H3K36M reduces H3K36me by directly impeding the activities of the histone methyltransferase NSD3 and the histone demethylase LSD2. Notably, we found that aberrant H3K27me3 levels induced by H3K36M expression is not a bona fide epigenetic mark in HNSCC since it requires continuous expression of H3K36M to be inherited. Moreover, increased sensitivity of H3K36M HNSCC models to PARP1/2 inhibitors solely depends on the increased H3K27me3 levels. Indeed, aberrantly high H3K27me3 levels decrease BRCA1 and FANCD2-dependent DNA repair, resulting in higher sensitivity to DNA breaks and replication stress. Finally, in support of our in vitro findings, a PARP1/2 inhibitor alone reduce tumor burden in a H3K36M HNSCC xenograft model with elevated H3K27me3, whereas in a H3K36M HNSCC xenograft model with consistent H3K27me3 levels, a combination of PARP1/2 inhibitors and agents that upregulate H3K27me3 proves to be successful. In conclusion, our findings underscore a delicate balance between H3K36 and H3K27 methylation, essential for maintaining genome stability. This equilibrium presents promising therapeutic opportunities for patients with H3K36me-deficient tumors.

cancer biology↗

bioRxiv2023

SERF2, an RNA G-quadruplex Binding Protein, promotes stress granule formation

Liquid-liquid phase transitions govern a wide range of protein-protein and protein-RNA interactions. Although the importance of multivalency and protein disorder in driving these transitions is clear, there is limited knowledge concerning the structural basis of phase transitions or the conformational changes that accompany this process. In this work, we found that a small human protein, SERF2, is important for the formation of stress granules. We determined the solution NMR structure ensemble of SERF2. We show that SERF2 specifically interacts with non-canonical tetrahelical RNA structures called G-quadruplexes, structures linked to stress granule formation. The biophysical amenability of both SERF2 and RNA G4 quadruplexes have allowed us to characterize the multivalent protein-RNA interactions involved in liquid-liquid phase transitions, the role that protein disorder plays in these transitions, identify the specific contacts involved, and describe how these interactions impact the structural dynamics of the components enabling a detailed understanding of the structural transitions involved in early stages of ribonucleoprotein condensate formation.

cell biology↗

bioRxiv2021

Multi-omics analysis of multiple glucose-sensing receptor systems in yeast

The yeast Saccharomyces cerevisiae has long been used to produce alcohol from glucose and other sugars. While much is known about glucose metabolism, relatively little is known about the receptors and signaling pathways that indicate glucose availability. Here we compare the two glucose receptor systems in S. cerevisiae. The first is a heterodimer of transporter-like proteins (transceptors), while the second is a seven-transmembrane receptor coupled to a large G protein (Gpa2) and two small G proteins (Ras1 and Ras2). Through comprehensive measurements of glucose-dependent transcription and metabolism, we demonstrate that the two receptor systems have distinct roles in glucose signaling: the G protein-coupled receptor directs carbohydrate and energy metabolism, while the transceptors regulate ancillary processes such as ribosome, amino acids, cofactor and vitamin metabolism. The large G protein transmits the signal from its cognate receptor, while the small G protein Ras2 (but not Ras1) integrates responses from both receptor pathways. Collectively, our analysis reveals the molecular basis for glucose detection and the earliest events of glucose-dependent signal transduction in yeast.

genomics↗

bioRxiv2021

Quantitative Profiling of Adaptation to Cyclin E Overproduction

Cyclin E/CDK2 drives cell cycle progression from G1 to S phase. Cyclin E overproduction is toxic to mammalian cells, although the gene encoding cyclin E (CCNE1) is overexpressed in some cancers. To gain insight into how cancer cells tolerate high cyclin E, we extensively characterized non-transformed epithelial cells throughout a time course of chronic cyclin E overproduction. Cells overproducing human cyclin E, but not cyclin D or cyclin A, briefly experienced truncated G1 phases, then endured a transient period of DNA replication origin underlicensing, replication stress, and severely impaired proliferation. Individual cells displayed substantial intercellular heterogeneity in cell cycle dynamics and CDK activity. Each phenotype improved rapidly despite maintaining high cyclin E-associated activity. Transcriptome analysis revealed that adapted cells downregulated a cohort of G1-regulated genes. Withdrawing cyclin E induction only partially reversed the intermediate licensing phenotype of adapted cells indicating that adaptation is at least partly independent of mutations. This study provides evidence that mammalian cyclin E/CDK inhibits origin licensing by an indirect mechanism through premature S phase onset and provides further insight into the relationship between CDK activity and licensing in mammals. It serves as an example of specific oncogene adaptation that may recapitulate molecular changes during tumorigenesis.

cell biology↗