Fig. 2

Prl-deficient zebrafish can survive only in brackish water.

(A) The curve of survival rates of wild-type and prl-deficient larvae in regular zebrafish egg water and system water (FW, 60–175 mg/L IOS) or brackish water (BW, 5060–5175 mg/L IOS) (n = 100). (B) The general morphological observations of wild-type larvae (B1-B5) and prl-deficient larvae (B6-B10) during 4–8 dpf. The prl-deficient larvae exhibit defects in swim bladder inflation after 5 dpf (B8-B10), curved bodies at 6 dpf (B8), and obvious edema at 7–8 dpf (B9, B10). (C) Major ion contents were measured with wild-type larvae and prl-deficient larvae at 6 dpf cultured in FW and BW. Cation contents were assessed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES) method and chloride assessed by chloride colorimetric assay kit. *significant difference (P < 0.05). At least twenty embryos were pooled as a sample for ion content analysis. (D) Representative healthy wild-type (left) and prl-deficient (right) adults cultured in brackish water at 100 dpf. IOS, Instant Ocean salts; dpf, days post-fertilization. E) Assessment of synthesized wild-type prl mRNA injection based on statistics of gas bladders inflated rates of wild-type larvae, prl-deficient larvae and prl-deficient larvae injected with prl mRNA at 5 dpf.