AUTHOR=Soga Tomoko , Nakajima Shingo , Parhar Ishwar S. 

TITLE=Expression of Repressor Element 1 Silencing Transcription Factor (REST) in Serotonin Neurons in the Adult Male Nile Tilapia (Oreochromis niloticus)

JOURNAL=Frontiers in Neuroanatomy

VOLUME=14

YEAR=2021

URL=https://www.frontiersin.org/journals/neuroanatomy/articles/10.3389/fnana.2020.599540

DOI=10.3389/fnana.2020.599540

ISSN=1662-5129

ABSTRACT=<p>Repressor element-1 silencing transcription factor (REST) is highly expressed in the dorsal raphe where serotonin (5-hydroxytryptamine, 5-HT) neurons are located. REST works as a transcription factor for the 5-HT receptor and tryptophan hydroxylase two-gene expression. We hypothesized that REST is co-expressed in 5-HT neurons, which, if demonstrated, would be useful to understand the mechanism of 5-HT dysfunction-related disorders such as negative emotions and depression. Therefore, the present study was designed to examine the expression of the <italic>REST</italic> gene in the brain (forebrain, midbrain, and hindbrain) of adult male Nile tilapia (<italic>Oreochromis niloticus</italic>) using rt-PCR. Besides, using immunocytochemistry, co-localization of the <italic>REST</italic> gene was examined in 5-HT neurons and with neuronal-/glial-cell markers. We found a high expression of the <italic>REST</italic> gene in the midbrain region of the dorsal raphe, an area of 5-HT neurons. Double-label immunocytochemistry showed neuron-specific expression of <italic>REST</italic> co-localized in 5-HT neurons in the dorsal and ventral parts of the periventricular pretectal nucleus, paraventricular organ, and dorsal and medial raphe nucleus. Since midbrain 5-HT neurons express REST, we speculate that REST may control 5-HT neuronal activity related to negative emotions, including depression.</p>