[Development of resources, technologies and services at the China Zebrafish Resource Center].

With the rapid growth of the Chinese zebrafish community, there is an increasing demand for various types of zebrafish-related resources and technologies. The China Zebrafish Resource Center (CZRC, web: http://zfish.cn) was established at the Institute of Hydrobiology (IHB), Chinese Academy of Sciences (CAS) in 2012. Till now, CZRC has built the largest zebrafish aquaculture unit in China, organized a resource bank containing more than 1200 zebrafish lines and more than 10 000 frozen sperm samples, among which over 200 mutant and transgenic lines were generated by CZRC. CZRC has established several technical supporting platforms, such as the zebrafish husbandry and health control program of international standard, a high-efficient gene manipulation technology platform, and a stable and efficient sperm cryopreservation technology platform. The main task of CZRC is to provide different types of services to zebrafish investigators in China and worldwide, such as resource services (e.g. zebrafish lines), technical services (e.g. gene knockout) and transgenic services, consultancy services (e.g. zebrafish husbandry and health consultation), and conference services [e.g. holding regular technical training courses and biennale Chinese Zebrafish Principal Investigator Meeting (CZPM)]. After five years' development, CZRC is now recognized as one of the three major resource centers in the global zebrafish community.

Zebrafish foxo3b negatively regulates canonical Wnt signaling to affect early embryogenesis.

FOXO genes are involved in many aspects of development and vascular homeostasis by regulating cell apoptosis, proliferation, and the control of oxidative stress. In addition, FOXO genes have been showed to inhibit Wnt/ß-catenin signaling by competing with T cell factor to bind to ß-catenin. However, how important of this inhibition in vivo, particularly in embryogenesis is still unknown. To demonstrate the roles of FOXO genes in embryogenesis will help us to further understand their relevant physiological functions. Zebrafish foxo3b gene, an orthologue of mammalian FOXO3, was expressed maternally and distributed ubiquitously during early embryogenesis and later restricted to brain. After morpholino-mediated knockdown of foxo3b, the zebrafish embryos exhibited defects in axis and neuroectoderm formation, suggesting its critical role in early embryogenesis. The embryo-developmental marker gene staining at different stages, phenotype analysis and rescue assays revealed that foxo3b acted its role through negatively regulating both maternal and zygotic Wnt/ß-catenin signaling. Moreover, we found that foxo3b could interact with zebrafish ß-catenin1 and ß-catenin2 to suppress their transactivation in vitro and in vivo, further confirming its role relevant to the inhibition of Wnt/ß-catenin signaling. Taken together, we revealed that foxo3b played a very important role in embryogenesis and negatively regulated maternal and zygotic Wnt/ß-catenin signaling by directly interacting with both ß-catenin1 and ß-catenin2. Our studies provide an in vivo model for illustrating function of FOXO transcription factors in embryogenesis.