Putative metalloprotease playing a role in the process of LR patterning. Binds 1 zinc ion per subunit. First expressed at stage 10.5 in the involuting marginal zone (IMZ) along a dorsal-high ventral-low gradient and, by stage 14 in cells of the circumblastoporal collar. Embryos with CRISPR-induced cirop null present heterotaxy phenotype (heart looping and intestine defects). No other ciliopathy-related phenotypes such as body curvature, kidney cysts or hydrocephalus are observed in cirop mutant embryos. Belongs to the peptidase M8 family.