Crawford M J, KhosrowShahian F, Liversage R A, Varmuza S L
Department of Biological Sciecnes, University of Windsor, ON, Canada.
Biochem Cell Biol. 2001;79(2):113-21.
We report the isolation and characterization of the Xenopus homolog to human T1 ANT (adenine nucleotide translocase). The 1290-nucleotide sequence contains initiation and termination signals, and encodes a conceptual protein of 298 amino acids. The sequence shares high amino acid identity with the mammalian adenine translocases. The transcript is present in unfertilized eggs, and it is expressed at higher levels during formation of the antero-posterior dorsal axis in embryos. Although low levels are expressed constitutively except in endodermal cells, adenine nucleotide translocase (ANT) expression is dynamically regulated during neurulation. At this stage, expression in ectoderm rapidly diminishes as the neural folds form, and then ANT expression increases slightly in mesoderm. At the culmination of neurulation, the neural tube briefly expresses ANT, and thereafter its expression predominates in the somitic mesoderm and also the chordoneural hinge. In addition, ANT expression is particularly high in the prosencephalon, the mesencephalon, the branchial arches, eye, and the otic vesicle. Treatment of embryos with retinoic acid has the effect of diminishing constitutive expression of ANT, but microinjection studies demonstrate that immediate and local repression cannot be induced in dorsal structures.
我们报道了非洲爪蟾中与人类T1 ANT（腺嘌呤核苷酸转位酶）同源物的分离与特性分析。1290个核苷酸的序列包含起始和终止信号，并编码一个由298个氨基酸组成的概念性蛋白质。该序列与哺乳动物的腺嘌呤转位酶具有高度的氨基酸同一性。该转录本存在于未受精卵中，并且在胚胎前后背轴形成过程中表达水平较高。尽管除了在内胚层细胞中组成性表达水平较低外，腺嘌呤核苷酸转位酶（ANT）在神经胚形成过程中受到动态调节。在此阶段，随着神经褶形成，外胚层中的表达迅速减少，然后中胚层中的ANT表达略有增加。在神经胚形成的顶点，神经管短暂表达ANT，此后其表达在体节中胚层以及脊神经铰链中占主导地位。此外，ANT在端脑、中脑、鳃弓、眼睛和耳泡中的表达特别高。用视黄酸处理胚胎具有减少ANT组成性表达的作用，但显微注射研究表明，不能在背侧结构中诱导立即和局部抑制。
