The role of the Rax gene in controlling daily rhythms of the mature pineal gland in mice lacking this gene

Deletion of Rax in the pineal gland did not affect its morphology, suggesting Rax is not essential for pineal gland development.

• Rax is crucial for eye development, leading to anophthalmia when deleted in the eye.
• The absence of Rax also results in the loss of the suprachiasmatic nucleus, indicating the importance of visual pathways for its development.
• Functional analyses showed a lack of a circadian clock in Rax conditional knockout mice.
• Aanat transcripts, which are vital for melatonin production, were undetectable in the knockout pineal gland under normal conditions.
• Isoproterenol injection induced some Aanat expression in the knockout mice, but levels remained significantly lower compared to Rax-proficient mice.
• These findings suggest that Rax may regulate pineal gene expression and influence melatonin synthesis through Aanat.

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