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The Photoreceptor Cells in Retina and Pineal Gland of Amphibian Hoplobatrachus rugulosus
Author(s) -
Liao Meng-Lin,
Lin Tzu-Cheun,
Chien Chung-Liang
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.09006
Subject(s) - xenopus , pineal gland , biology , amphibian , retina , microbiology and biotechnology , african clawed frog , harderian gland , pinealocyte , western blot , anatomy , endocrinology , neuroscience , melatonin , genetics , gene , ecology
Hoplobatrachus rugulosus , commonly referred to as tiger‐skinned frog, is to be chosen the animal model in this study. It has been found that both chicken α‐internexin and zebrafish inaa (an ortholog of mammalian α‐internexin) were developmentally distributed not only in photoreceptors of retina but also in the photoreceptor‐like cells of the pineal gland from our previous studies. However, from an evolutionary point of view, there is still lack of evidence to illustrate the temporal and spatial distribution of frog α‐internexin protein in the developing pineal gland. According to other studies about Xenopus laevis , the animal model that is usually used for amphibian developmental research, the mRNA sequence which encodes Xenopus α‐internexin had been identified as “xefiltin”. Although H. rugulosus is not the same species with X. laevis , both of them are classified in the same order. The aims of this study is to characterize the expression pattern of α‐internexin‐like proteins, internexin neuronal intermediate filament protein alpha S homeolog (ina.S) and low molecular weight neuronal intermediate filament S homeolog (nif.S) which might be expressed in the developing retina and the pineal gland of the tiger‐skinned frog. Thus, the specific antibodies were generated to detect the frog α‐internexin‐like proteins and to confirm the distribution of these proteins in the developing frog retina as well as the pineal gland by western blot and immunohistochemistry. Furthermore, the markers applied to detect the photoreceptor cell in the retina and the pineal gland are recoverin and XAP1, both of them are reported to be specific to photoreceptors. Based on the distribution patterns in frog retina, immunopositive staining of anti‐nif.S could be observed in the outer segment of photoreceptors, but anti‐ina.S could only be found in retinal neurons. In the pineal gland, both photoreceptor markers, recoverin and XAP1, could be detected. The α‐internexin‐like protein, ina.S and nif.S, could be detected only in a few photoreceptor‐like cells at the early stage of the frog pineal gland. In summary, the distribution patterns of photoreceptor cells in retina and in pineal gland of developing tiger‐skinned frogs has been characterized in this study. It can be concluded that XAP1 could be a good marker to identify the photoreceptor cells in the developing pineal gland of frogs. Support or Funding Information Grant Sponsor Ministry of Science and Technology, Taiwan; Grant Number: MOST 108‐2312‐B‐002‐030‐MY2.