Generating adamts13-/- Zebrafish via CRISPR/Cas9 Gene Editing.

The zebrafish (Danio rerio) is a powerful vertebrate model for studying hematologic and thrombotic diseases due to its genetic tractability and conservation of hemostatic pathways with humans. In this chapter, we describe a detailed workflow for generating adamts13 knockout zebrafish using CRISPR/Cas9-mediated genome editing. Methods include the design and preparation of guide RNAs, Cas9 mRNA synthesis, and embryo microinjection at the one-cell stage. Alternative strategies for gRNA generation, including synthetic crRNA:tracrRNA duplexes, are also outlined. We provide protocols for screening founder fish, genotyping, and establishing stable mutant lines through outcrossing, thereby minimizing potential off-target effects. Practical notes on embryo handling, RNA stability, and contamination prevention are highlighted to ensure reproducibility. Together, these procedures establish a robust framework for creating zebrafish loss-of-function models, enabling mechanistic studies of ADAMTS13 function in vivo and advancing the exploration of thrombotic disease pathophysiology. This approach can be readily adapted to knock out other genes or introduce specific mutations in zebrafish simply by altering the gRNA sequence.