• Korean Journal of Ichthyology
• /
• v.20 no.3
• /
• pp.167-172
• /
• 2008

The Korean bitterling, Acheilognathus signifer (Osteichthyes Cyprinidae), is an endemic and endangered species in Korea. During developmental stages, a small number of oculocutaneous albinism (with colorless body and eyeballs) were observed in the species. In order to investigate histological differences between normal and albinic bitterling, the dorsal skin and choroid-retina of the eyes were taken. The skin and eyes of normal and albino bitterling were similar in structure except for the presence or density of pigment cells. In normal bitterling, the epidermal melanocytes and dermal melanophores were abundantly developed in both the skin and epidermis of the eyes. But in the albino, the dorsal skin had few melanins, and the pigment cells over the choroid-retina pigment epithelium and iris of the eye were very small.

• Korean Journal of Ichthyology
• /
• v.22 no.2
• /
• pp.96-104
• /
• 2010

During an artificial breeding as a part of restoration of the endangered Korean bitterling Acheilognathus signifer, a small number of individuals exhibiting oculocutaneous albinism were produced. We compared the pigmentation and morphology of normal and albinic bitterlings by histological examination of skin samples obtained from 10 regions on the body, fins, and eyes. There were no differences in morphometry and in general morphology of skin between them. In normal bitterlings, pigment cells were better developed in the dorsal region, the upper part of caudal peduncle region, the choroid-retinal epithelium and iris than in other areas. In the albinic bitterling, however, pigment cells were present only in three parts of the dorsal region, the caudal and dorsal fin, which had few melanin cells. Albinic bitterlings also displayed deficient pigmentation in the choroid-retina pigment epithelium and iris. Although they had different pigmentation aspects in distribution and development between normal and albinic bitterlings, melanin cells were mainly present in the dorsal regions of the skin and eyes where are exposed directly to light.

• Molecules and Cells
• /
• v.44 no.3
• /
• pp.168-178
• /
• 2021

The retinal pigment epithelium (RPE) forms a monolayer sheet separating the retina and choroid in vertebrate eyes. The polarized nature of RPE is maintained by distributing membrane proteins differentially along apico-basal axis. We found the distributions of these proteins differ in embryonic, post-natal, and mature mouse RPE, suggesting developmental regulation of protein trafficking. Thus, we deleted tumor susceptibility gene 101 (Tsg101), a key component of endosomal sorting complexes required for transport (ESCRT), in embryonic and mature RPE to determine whether ESCRT-mediated endocytic protein trafficking correlated with the establishment and maintenance of RPE polarity. Loss of Tsg101 severely disturbed the polarity of RPE, which forms irregular aggregates exhibiting non-polarized distribution of cell adhesion proteins and activation of epidermal growth factor receptor signaling. These findings suggest that ESCRT-mediated protein trafficking is essential for the development and maintenance of RPE cell polarity.