Fig. 4

The expression of cathepsin L and CTSB-like during zebrafish embryogenesis. Wild-type embryos were analyzed with whole-mount  in situhybridization (WISH) at the indicated stages with antisense riboprobes against cathepsin L ( A) and CSTB-like ( B) for mRNA distribution. ( A) No appreciable signal for cathepsin L was observed in embryos before 8 hpf. Signals were significant in 12 hpf embryos at anterior prechordal plate (app) and subsequently in hatching gland (hg) at later stages. Signals were also abundant in the head region and swim bladder (sb) of 4-dpf larvae, which can be observed more clearly in a post-WISH cross-section at the trunk region (dash line and black arrow in inset). ( B) Intensive expression and homogenous distribution of CSTB-like transcripts were observed in embryos before 4 hpf. Signals became focused anteriorly in 1 dpf embryos and gradually diminished, as development proceeded, but nonetheless persistent in the trunk region along the vessels. Significant distribution appeared in the heart and the uninflated swim bladder area of 4 dpf larvae and became enriched in the region surrounding swim bladder at 5 dpf. app, anterior prechordal plate; h, heart; hg, hatching gland; sb, swim bladder.