Liang V C, Sedgwick T, Shi Y B
Laboratory of Molecular Embryology NICHD/NIH, Bethesda, MD 20892-5431, USA.
Cell Res. 1997 Dec;7(2):179-93. doi: 10.1038/cr.1997.19.
The complex transformation of a tadpole to a frog during amphibian development is under the control of thyroid hormone (T3). T3 is known to regulate gene transcription through its nuclear receptors. We have previously isolated many genes which are up-regulated by T3 in the intestine of Xenopus laevis tadpoles. We have now cloned a full-length cDNA for one such gene (IU12). Sequence analysis shows that the IU12 cDNA encodes a plasma membrane protein with 12 transmembrane domains and homologous to a mammalian gene associated with cell activation and organ development. Similarly, we have found that IU12 is activated during intestinal remodeling when both cell death and proliferation take place. Furthermore, IU12 is an early T3-response gene and its expression in the intestine during T3-induced metamorphosis mimics that during normal development. These results argue for a role of IU12 in the signal transduction pathways leading to intestinal metamorphosis.
在两栖动物发育过程中，蝌蚪向青蛙的复杂转变受甲状腺激素（T3）的控制。已知T3通过其核受体调节基因转录。我们之前已在非洲爪蟾蝌蚪的肠道中分离出许多受T3上调的基因。我们现已克隆出一个此类基因（IU12）的全长cDNA。序列分析表明，IU12 cDNA编码一种具有12个跨膜结构域的质膜蛋白，与一个与细胞激活和器官发育相关的哺乳动物基因同源。同样，我们发现，在肠道重塑过程中，当细胞死亡和增殖同时发生时，IU12被激活。此外，IU12是一个早期T3反应基因，其在T3诱导的变态发育过程中在肠道中的表达与正常发育过程中的表达相似。这些结果表明IU12在导致肠道变态发育的信号转导途径中发挥作用。
