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Invest Ophthalmol Vis Sci April 1, 2015; 56 (4): 2486-97.

Ornithine-δ-Aminotransferase Inhibits Neurogenesis During Xenopus Embryonic Development.

Peng Y , Cooper SK , Li Y , Mei JM , Qiu S , Borchert GL , Donald SP , Kung HF , Phang JM .

In humans, deficiency of ornithine-δ-aminotransferase (OAT) results in progressive degeneration of the neural retina (gyrate atrophy) with blindness in the fourth decade. In this study, we used the Xenopus embryonic developmental model to study functions of the OAT gene on embryonic development. We cloned and sequenced full-length OAT cDNA from Xenopus oocytes (X-OAT) and determined X-OAT expression in various developmental stages of Xenopus embryos and in a variety of adult tissues. The phenotype, gene expression of neural developmental markers, and enzymatic activity were detected by gain-of-function and loss-of-function manipulations. We showed that X-OAT is essential for Xenopus embryonic development, and overexpression of X-OAT produces a ventralized phenotype characterized by a small head, lack of axial structure, and defective expression of neural developmental markers. Using X-OAT mutants based on mutations identified in humans, we found that substitution of both Arg 180 and Leu 402 abrogated both X-OAT enzymatic activity and ability to modulate the developmental phenotype. Neurogenesis is inhibited by X-OAT during Xenopus embryonic development. Neurogenesis is inhibited by X-OAT during Xenopus embryonic development, but it is essential for Xenopus embryonic development. The Arg 180 and Leu 402 are crucial for these effects of the OAT molecule in development.

PubMed ID: 25783604
PMC ID: PMC4554259
Article link: Invest Ophthalmol Vis Sci
Grant support: [+]
Genes referenced: oat
Morpholinos: oat.1.L


Article Images: [+] show captions
References [+] :
Baumgartner, Hyperammonemia with reduced ornithine, citrulline, arginine and proline: a new inborn error caused by a mutation in the gene encoding delta(1)-pyrroline-5-carboxylate synthase. 2001, Pubmed

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