This paper systematically summarises the key scientific issues in the study of the antiviral innate immune system of amphioxus, highlighting the recent progress in the areas of diversity of pattern recognition receptors (PRRs), conservatism and innovativeness of signaling pathways, complexity of regulatory networks of effector molecules, and their evolutionary relevance to the vertebrate immune system. Through in-depth discussion of the molecular types, virus recognition specificity, and signalling cascade activation mechanism of amphioxus PRRs and spatial and temporal expression regulation of amphioxus effector molecules (e.g. antimicrobial peptides, interferon-inducible proteins), the multilevel defence strategy of its antiviral immune response was revealed by combining with the comparative immunology perspective. The study paid special attention to the synergistic mode of action of Toll-like receptors (TLRs) and Retinoic acid-inducible gene-Ⅰ-like receptors (RLRs), the inter-regulatory network of NF-κB and Interferon Regulatory Factor (IRF) transcription factors, and the molecular basis of the immune memory-like phenomenon. On this basis, this paper provides a theoretical explanation of the transitional position of the antiviral immune system of amphioxus in the evolution of vertebrate immunity, and prospectively suggests that future studies should focus on the horizontal expansion and functional differentiation of the immune gene family, the evolutionary trajectory of the epigenetic regulatory elements, and the driving mechanism of the evolution of immune adaptations by environmental stresses, which would provide a key empirical basis for the analysis of the molecular origins of the innate immune system in vertebrates.

Sex determination and differentiation play crucial biological roles in sexual reproduction in vertebrates, including zebrafish. Nevertheless, the intricate molecular mechanisms governing these processes have remained enigmatic. In this study, we showed a pivotal role played by zinc finger GATA-like protein-1 (Zglp-1) in sex differentiation in zebrafish. Our findings revealed that homozygous mutants having no Zglp-1 exhibited a female-to-male sex reversal, ultimately resulting in the development of fertile males. Within the pivotal phase of sexual differentiation, zglp-1^−/− zebrafish demonstrated a gene expression pattern that was skewed toward a male phenotype. Notably, the expression of amh was upregulated, while the expression of cyp19a1a was not sustained. Furthermore, our data revealed a direct interaction between the zinc fingers of Zglp-1 and Sf-1, which inhibited the ability of Sf-1 to activate the amh promoter. This interaction was crucial for regulating sex differentiation. Moreover, we observed alterations in gonadal cell proliferation and apoptosis in zglp-1^−/− zebrafish, which partially contributed to the sexual fate selection. Overall, our findings firmly established Zglp-1 as a crucial regulator of sex differentiation in zebrafish, offering deep insights into the intricate molecular mechanisms that govern sex determination and differentiation in vertebrates.