Figure 4

In situ localization of omTERT mRNA in livers (A-C) and testes (D-F) of marine medaka. (A) Liver under normoxia (6.4 mg O₂ L^-1). Weak expression of omTERT mRNA (blue) is observed in liver parenchyma. (B) Liver exposed to hypoxia (1.8 mg O₂ L^-1) for 96 h. Induced expression of omTERT mRNA (blue) is evident, particularly at the posterior or caudal region of liver (Lp) as compared to the rostal or anterior region (La) (see insert at low magnification). (C) Adjacent liver section of (B) hybridized with an omTERT sense riboprobe as a negative control. (D) Testis under normoxia (6.4 mg O₂ L^-1). Expression of omTERT mRNA (blue) is strong in cysts containing spermatogonia (SG) and spermatocyte (SC), moderate in differentiating spermatids (ST) and absent in mature spermatozoa (SP) (red). (E) Testis exposed to hypoxia (1.8 mg O₂ L^-1) for 96 h. Induction of omTERT mRNA (blue) is conspicuous in spermatogonia (SG) and less prominent in other testicular cells. (F) Adjacent testis section of (E) hybridized with an omTERT sense riboprobe as a negative control. Scale bars = 50 μm, except insert of (b) = 200 μm.