Biology subjects

LaVigne, C. A.

Publications and source records attributed to LaVigne, C. A..

3 recordsLinked to original sources

bioRxiv2025

Plagl1 and Lrrc58 control mammalian body size by triggering target-directed microRNA degradation of miR-322 and miR-503

Precise control of microRNA (miRNA) expression is critical during development. An important mechanism of miRNA regulation is target-directed microRNA degradation (TDMD), a pathway in which the binding of miRNAs to specialized trigger RNAs induces ubiquitylation and decay of associated Argonaute (AGO) proteins by the ZSWIM8 ubiquitin ligase. Concomitant release of miRNAs results in their rapid turnover. ZSWIM8-deficient mice exhibit reduced body size, cardiopulmonary and neurodevelopmental defects, and perinatal lethality. Despite widespread dysregulation of miRNAs in these animals, the vast majority of presumptive trigger RNAs that induce decay of ZSWIM8-regulated miRNAs remain undefined. Here, using AGO crosslinking and sequencing of hybrids (AGO-CLASH), a high-throughput method for identifying miRNA binding sites, we report the identification of Plagl1 as a TDMD trigger for miR-322-5p, and Lrrc58 and Malat1 as TDMD triggers for miR-503-5p in mouse embryonic fibroblasts (MEFs). In mice, deletion of the miR-322-5p and miR-503-5p trigger sites in the Plagl1 and Lrrc58 3' UTRs, respectively, abrogated TDMD of these miRNAs and resulted in miR-322/503-dependent embryonic growth restriction, recapitulating a key feature of the Zswim8--/-- phenotype. Thus, Plagl1 and Lrrc58 act as triggers for degradation of miR-322-5p and miR-503-5p, revealing a noncoding function for these mRNAs as regulators of mammalian body size.

molecular biology↗

bioRxiv2024

Engineering an fgfr4 knockout zebrafish to study its role in development and disease

Fibroblast growth factor receptor 4 (FGFR4) has a role in many biological processes, including lipid metabolism, tissue repair, and vertebrate development. In recent years, FGFR4 overexpression and activating mutations have been associated with numerous adult and pediatric cancers. As such, FGFR4 presents an opportunity for therapeutic targeting which is being pursued in clinical trials. To understand the role of FGFR4 signaling in disease and development, we generated and characterized three alleles of fgfr4 knockout zebrafish strains using CRISPR/Cas9. To generate fgfr4 knockout crispants, we injected single-cell wildtype zebrafish embryos with fgfr4 targeting guide RNA and Cas9 proteins, identified adult founders, and outcrossed to wildtype zebrafish to create an F1 generation. The generated mutations introduce a stop codon within the second Ig-like domain of Fgfr4, resulting in a truncated 215, 223, or 228 amino acid Fgfr4 protein compared to 922 amino acids in the full-length protein. All mutant strains exhibited significantly decreased fgfr4 mRNA expression during development, providing evidence for successful knockout of fgfr4 in mutant zebrafish. We found that, consistent with other Fgfr4 knockout animal models, the fgfr4 mutant fish developed normally; however, homozygous fgfr4 mutant zebrafish were significantly smaller than wildtype fish at three months post fertilization. These fgfr4 knockout zebrafish lines are a valuable tool to study the role of FGFR4 in vertebrate development and its viability as a potential therapeutic target in pediatric and adult cancers, as well as other diseases.

developmental biology↗

bioRxiv2022

Zebrafish her3 knockout impacts developmental and cancer-related gene signatures

HES3 is a basic helix-loop-helix transcription factor that regulates neural stem cell renewal during development. HES3 overexpression is predictive of reduced overall survival in patients with fusion-positive rhabdomyosarcoma, a pediatric cancer that resembles immature and undifferentiated skeletal muscle. However, the mechanisms of HES3 cooperation in fusion-positive rhabdomyosarcoma are unclear and are likely related to her3/HES3s role in neurogenesis. To investigate HES3s function during development, we generated a zebrafish CRISPR/Cas9 knockout of her3, the zebrafish ortholog of HES3. Loss of her3 is not embryonic lethal and adults exhibit expected Mendelian ratios. Embryonic her3 zebrafish mutants are significantly smaller than wildtype and a subset present with lens defects as adults. Transcriptomic analysis of her3 mutant embryos indicates that genes involved in organ development, such as pctp and grinab, are significantly downregulated. Further, differentially expressed genes in her3 knockout embryos are enriched for HOX and SOX10 motifs. Several cancer-related gene pathways are impacted, including the inhibition of matrix metalloproteinases. Altogether, this new model is a powerful system to study her3/HES3-mediated neural development and its misappropriation in cancer contexts. Summary StatementHere, we generate and characterize a zebrafish her3/HES3 knockout to elucidate the functional role of her3/HES3, a transcriptional repressor, in neural development and tumorigenic processes.

developmental biology↗