Biology subjects

Bazzini, A.

Publications and source records attributed to Bazzini, A..

3 recordsLinked to original sources

bioRxiv2026

Cth1 is essential for gametogenesis and fertility in zebrafish

Infertility frequently arises from defects in germ cells and early embryonic transition. Successful fertilization depends on the developmental competence and molecular integrity of mature gametes from both parents, which are established through tightly coordinated programs of RNA regulation, metabolism, and genome maintenance. In our previous work, we identified Cth1 as a maternally regulated RNA decay factor essential for early embryonic development, acting through spatiotemporal control of maternal transcript clearance. Interestingly, Cth1 loss of function in adults also resulted in infertility, suggesting an additional and unexplored role during gametogenesis. Here, we extend these findings by defining the gametogenic function of Cth1 in zebrafish. Through detailed phenotypic, cytological and molecular characterization of Cth1 loss of function mutants, we show that Cth1 is highly enriched in germ cells and early embryos and is spatio-temporally localized across oogenesis and early development. Loss of Cth1 causes severe defects in early oogenesis and spermatogenesis, resulting in complete infertility in males and females. Mutant germ cells display transcriptomic changes consistent with metabolic and translational dysregulation, increased DNA damage, and striking abnormalities in gamete morphology. Together, these findings identify Cth1 as essential for gamete quality and fertility. Our study suggests a link between RNA decay mediated regulation of metabolism and genome integrity during germ cell development and reveals disruption of post-transcriptional control as a potential mechanism underlying infertility.

developmental biology↗

bioRxiv2024

Enhanced RNA-targeting CRISPR-Cas technology in zebrafish

CRISPR-Cas13 systems are widely used in basic and applied sciences. However, its application has recently generated controversy due to collateral activity in mammalian cells and mouse models. Moreover, its efficiency could be improved in vivo. Here, we optimized transient formulations as ribonucleoprotein complexes or mRNA-gRNA combinations to enhance the CRISPR-RfxCas13d system in zebrafish. We i) used chemically modified gRNAs to allow more penetrant loss-of-function phenotypes, ii) improved nuclear RNA-targeting, and iii) compared different computational models and determined the most accurate to predict gRNA activity in vivo. Furthermore, we demonstrated that transient CRISPR-RfxCas13d can effectively deplete endogenous mRNAs in zebrafish embryos without inducing collateral effects, except when targeting extremely abundant and ectopic RNAs. Finally, we implemented alternative RNA-targeting CRISPR-Cas systems with reduced or absent collateral activity. Altogether, these findings contribute to CRISPR-Cas technology optimization for RNA targeting in zebrafish through transient approaches and assist in the progression of in vivo applications.

developmental biology↗

bioRxiv2021

A community-driven roadmap to advance research on translated open reading frames detected by Ribo-seq

Ribosome profiling (Ribo-seq) has catalyzed a paradigm shift in our understanding of the translational vocabulary of the human genome, discovering thousands of translated open reading frames (ORFs) within long non-coding RNAs and presumed untranslated regions of protein-coding genes. However, reference gene annotation projects have been circumspect in their incorporation of these ORFs due to uncertainties about their experimental reproducibility and physiological roles. Yet, it is indisputable that certain Ribo-seq ORFs make stable proteins, others mediate gene regulation, and many have medical implications. Ultimately, the absence of standardized ORF annotation has created a circular problem: while Ribo-seq ORFs remain unannotated by reference biological databases, this lack of characterisation will thwart research efforts examining their roles. Here, we outline the initial stages of a community-led effort supported by GENCODE / Ensembl, HGNC and UniProt to produce a consolidated catalog of human Ribo-seq ORFs.

genomics↗