Fig. 2.

ouro1 and ouro2 are expressed in the skin during metamorphosis. (A) Northern blot analysis for ouro1 expression in J strain tadpoles. Tail and trunk skin tissues were isolated from various stages of tadpoles as indicated. A representative blot is shown (Upper Left), because five independent sets of experiments showed basically the same results. Ribosomal RNA visualized by ethidium bromide as a loading control (Lower Left). Relative expression levels were calculated using the image J software (Right). (B) RT-PCR with J strain tadpoles. Tail and trunk skin tissues as indicated were analyzed for ouro1, ouro2, Xenopus adult keratin (xak-b), Xenopus larval keratin (xlk), and Xenopus rpl8 (rpl8) as an internal control. -RT, rpl8 without RT. (C) Western blot analysis for Ouro1 and Ouro2 with J strain tadpoles. Tail and trunk skin cell lysates were used. (D) WISH with albino (non-J strain) X. laevis tadpoles. ouro1 antisense probe was used for tadpoles at stage 55 (n = 7), 58 (n = 7), and 62 (n = 3). ouro1 sense probe was used as a negative control for tadpoles at stage 58 (n = 5). Positive signals in blue were reproducibly detected in the tail and trunk (stage 55) or in the tail (stages 58 and 62). Arrowheads show the boundary between the tail and trunk region. (E) The vertical section of the tadpole at stage 62 after WISH using ouro1 antisense probe. The section includes the boundary between the tail and trunk skin as indicated. Purple signals are specifically seen in the tail epidermis (n = 2). ep, epidermis.