Selected Grantee Publications
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- 24 results found
- Aquatic Vertebrate Models
- 2025
- 2021
De Novo and Inherited Variants in DDX39B Cause a Novel Neurodevelopmental Syndrome
Booth et al., Brain. 2025.
https://academic.oup.com/brain/advance-article/doi/10.1093/brain/awaf035/8004980?login=true
DDX39B is a core component of the TRanscription-EXport (TREX) super protein complex. Recent studies have highlighted the important role of TREX subunits in neurodevelopmental disorders. Researchers describe a cohort of six individuals (male and female) from five families with disease-causing de novo missense variants or inherited splice-altering variants in DDX39B. Three individuals in the cohort are affected by mild to severe developmental delay, hypotonia, history of epilepsy or seizure, short stature, skeletal abnormalities, variable dysmorphic features, and microcephaly. Using a combination of patient genomic and transcriptomic data, in silico modeling, in vitro assays, and in vivo Drosophila and zebrafish models, this study implicates disruption of DDX39B in a novel neurodevelopmental disorder called TREX-complex-related neurodevelopmental syndrome. Supported by ORIP (U54OD030165).
Differentiation Success of Reprogrammed Cells Is Heterogeneous In Vivo and Modulated by Somatic Cell Identity Memory
Zikmund et al., Stem Cell Reports. 2025.
https://pubmed.ncbi.nlm.nih.gov/40086446
Nuclear reprogramming can change cellular fates, yet reprogramming efficiency is low, and the resulting cell types are often not functional. Researchers used nuclear transfer to Xenopus eggs to follow single cells during reprogramming in vivo. Results showed that the differentiation success of reprogrammed cells varies across cell types and depends on the expression of genes specific to the previous cellular identity. Subsets of reprogramming-resistant cells fail to form functional cell types and undergo cell death or disrupt normal body patterning. Reducing expression levels of genes specific to the cell type of origin leads to better reprogramming and improved differentiation trajectories. This study demonstrates that failing to reprogram in vivo is cell type specific and emphasizes the necessity of minimizing aberrant transcripts of the previous somatic identity for improving reprogramming. Supported by ORIP (R24OD031956).
Enhanced RNA-Targeting CRISPR-Cas Technology in Zebrafish
Moreno-Sánchez et al., Nature Communications. 2025.
https://pubmed.ncbi.nlm.nih.gov/40091120
CRISPR-Cas13 RNA-targeting systems, widely used in basic and applied sciences, have generated controversy because of collateral activity in mammalian cells and mouse models. In this study, researchers optimized transient formulations as ribonucleoprotein complexes or mRNA-gRNA combinations to enhance the CRISPR-RfxCas13d system in zebrafish. Researchers used chemically modified gRNAs to allow more penetrant loss-of-function phenotypes, improve nuclear RNA targeting, and compare different computational models to determine the most accurate prediction of gRNA activity in vivo. Results demonstrate that transient CRISPR-RfxCas13d can effectively deplete endogenous mRNAs in zebrafish embryos without inducing collateral effects, except when targeting extremely abundant and ectopic RNAs. Their findings contribute to CRISPR-Cas technology optimization for RNA targeting in zebrafish through transient approaches and advance in vivo applications. Supported by ORIP (R21OD034161), NICHD, and NIGMS.
HDAC Inhibitor Titration of Transcription and Axolotl Tail Regeneration
Voss et al., Frontiers in Cell and Development Biology. 2021.
https://pubmed.ncbi.nlm.nih.gov/35036404/
New patterns of gene expression are enacted and regulated during tissue regeneration. Romidepsin, an FDA-approved HDAC inhibitor, potently blocks axolotl embryo tail regeneration by altering initial transcriptional responses to injury. Regeneration inhibitory concentrations of romidepsin increased and decreased the expression of key genes. Single-nuclei RNA sequencing at 6 HPA illustrated that key genes were altered by romidepsin in the same direction across multiple cell types. These results implicate HDAC activity as a transcriptional mechanism that operates across cell types to regulate the alternative expression of genes that associate with regenerative success versus failure outcomes. Supported by ORIP (P40OD019794, R24OD010435, R24OD021479), NICHD, and NIGMS.
Precise Visuomotor Transformations Underlying Collective Behavior in Larval Zebrafish
Harpaz et al., Nature Communications. 2021.
https://www.nature.com/articles/s41467-021-26748-0
Sensory signals from neighbors, analyzed in the visuomotor stream of animals, is poorly understood. The authors studied aggregation behavior in larval zebrafish and found that over development larvae transition from over dispersed groups to tight shoals. Young larvae turn away from virtual neighbors by integrating and averaging retina-wide visual occupancy within each eye, and by using a winner-take-all strategy for binocular integration. Observed algorithms accurately predict group structure over development. These findings allow testable predictions regarding the neuronal circuits underlying collective behavior in zebrafish. Supported by ORIP (R43OD024879, R44OD024879) and NINDS.
Collective Behavior Emerges from Genetically Controlled Simple Behavioral Motifs in Zebrafish
Harpaz et al., Science Advances. 2021.
https://www.science.org/doi/10.1126/sciadv.abi7460
Harpaz et al. report that zebrafish regulate their proximity and alignment with each other at early larval stages. Two visual responses (one measuring relative visual field occupancy and one accounting for global visual motion), account for emerging group behavior. Mutations in genes known to affect social behavior in humans perturb these reflexes in individual larval zebrafish and change their emergent collective behaviors. Model simulations show that changes in these two responses in individual mutant animals predict well the distinctive collective patterns that emerge in a group. Hence, group behaviors reflect in part genetically defined primitive sensorimotor “motifs” evident in young larvae. Supported by ORIP (R43OD024879, R44OD024879) and NINDS.
Whole-Organism 3D Quantitative Characterization of Zebrafish Melanin by Silver Deposition Micro-CT
Katz et al., eLife. 2021.
https://www.biorxiv.org/content/10.1101/2021.03.11.434673v1
This research team combined micro-computed tomography (CT) with a novel application of ionic silver staining to characterize melanin distribution in whole zebrafish larvae. The resulting images enabled whole-body, computational analyses of regional melanin content and morphology. Normalized micro-CT reconstructions of silver-stained fish consistently reproduced pigment patterns seen by light microscopy and allowed direct quantitative comparisons of melanin content. Silver staining of melanin for micro-CT provides proof-of-principle for whole-body, 3D computational phenomic analysis of a specific cell type at cellular resolution. Advances such as this in whole-organism, high-resolution phenotyping provide superior context for studying the phenotypic effects of genetic, disease, and environmental variables. Supported by ORIP (R24OD018559).
MIC-Drop: A Platform for Large-scale In Vivo CRISPR Screens
Parvez et al., Science. 2021.
https://pubmed.ncbi.nlm.nih.gov/34413171/
CRISPR screens in animals are challenging because generating, validating, and keeping track of large numbers of mutant animals is prohibitive. These authors introduce Multiplexed Intermixed CRISPR Droplets (MIC-Drop), a platform combining droplet microfluidics, single-needle en masse CRISPR ribonucleoprotein injections, and DNA barcoding to enable large-scale functional genetic screens in zebrafish. In one application, they showed that MIC-Drop could identify small-molecule targets. Furthermore, in a MIC-Drop screen of 188 poorly characterized genes, they discovered several genes important for cardiac development and function. With the potential to scale to thousands of genes, MIC-Drop enables genome-scale reverse genetic screens in model organisms. Supported by ORIP (R24OD017870), NIGMS, and NHLBI.
The Bowfin Genome Illuminates the Developmental Evolution of Ray-Finned Fishes
Thompson et al., Nature Genetics. 2021.
https://www.nature.com/articles/s41588-021-00914-y
The bowfin (Amia calva) is a ray-finned fish that possesses a unique suite of ancestral and derived phenotypes, which are key to understanding vertebrate evolution. The phylogenetic position of bowfin as a representative of neopterygian fishes, its archetypical body plan and its unduplicated and slowly evolving genome make bowfin a central species for the genomic exploration of ray-finned fishes. Here the authors present a chromosome-level genome assembly for bowfin that enables gene-order analyses, settling long-debated neopterygian phylogenetic relationships. These resources connect developmental evolution among bony fishes, further highlighting the bowfin's importance for illuminating vertebrate biology and diversity in the genomic era. Supported by ORIP (R01OD011116).
TGF-β1 Signaling Is Essential for Tissue Regeneration in the Xenopus Tadpole Tail
Nakamura et al., Biochemical and Biophysical Research Communications. 2021.
https://www.sciencedirect.com/science/article/pii/S0006291X21008731
Amphibians, such as Xenopus tropicalis, exhibit a remarkable capacity for tissue regeneration after traumatic injury. Nakamura et al. show that inhibition of TGF-β1 function prevents tail regeneration in Xenopus tropicalis tadpoles. CRISPR-mediated knock-out (KO) of tgfb1 retards tail regeneration; the phenotype of tgfb1 KO tadpoles can be rescued by injection of tgfb1 mRNA. Cell proliferation, critical for tissue regeneration, is downregulated in tgfb1 KO tadpoles; tgfb1 KO reduces the expression of phosphorylated Smad2/3 (pSmad2/3). These results show that TGF-β1 regulates cell proliferation through the activation of Smad2/3. They propose that TGF-β1 plays a critical role in TGF-β receptor-dependent tadpole tail regeneration in Xenopus. Supported by ORIP (P40OD010997, R24OD030008).