Shoji H, Nakamura T, van den Eijnden-van Raaij A J, Sugino H
Institute for Enzyme Research, University of Tokushima, Japan.
Biochem Biophys Res Commun. 1998 May 19;246(2):320-4. doi: 10.1006/bbrc.1998.8613.
We have identified a novel type II activin receptor, called type IIA-N, the expression of which was induced during the neural differentiation of murine P19 embryonal carcinoma cells (P19 cells). P19 cells differentiate into several cell types dependent on the culture conditions. The induction of type IIA-N mRNA occurred predominantly in conjunction with neural differentiation. Sequence analysis of a cDNA clone for type IIA-N indicated that type IIA-N had a 24 bp insertion in the juxtamembrane region of the type IIA activin receptor suggesting that it is an alternative splicing product of the type IIA gene. Type IIA-N was also identified in human and Xenopus, and the amino acid sequences of three species were completely conserved. The expression of type IIA-N mRNA was specifically detected in neuroblastoma cells among several activin responsive cell lines. In vivo expression of type IIA-N mRNA was detected only in the neural tissues such as brain and spinal cord in adult mouse, by RT-PCR. Furthermore, its expression in developing Xenopus embryos was restricted to the neurula and later stages. These results suggest that the expression of type IIA-N is specific to neural cells and mediates neural differentiation-specific activin signaling.
我们鉴定出一种新型的II型激活素受体，称为IIA-N型，其表达在小鼠P19胚胎癌细胞（P19细胞）的神经分化过程中被诱导。P19细胞根据培养条件可分化为多种细胞类型。IIA-N型mRNA的诱导主要与神经分化同时发生。对IIA-N型cDNA克隆的序列分析表明，IIA-N型在IIA型激活素受体的近膜区域有一个24bp的插入，这表明它是IIA基因的一种选择性剪接产物。在人和非洲爪蟾中也鉴定出了IIA-N型，三个物种的氨基酸序列完全保守。在几种激活素反应性细胞系中，仅在神经母细胞瘤细胞中特异性检测到IIA-N型mRNA的表达。通过逆转录聚合酶链反应（RT-PCR），在成年小鼠体内仅在脑和脊髓等神经组织中检测到IIA-N型mRNA的表达。此外，其在非洲爪蟾发育胚胎中的表达仅限于神经胚期及以后阶段。这些结果表明，IIA-N型的表达对神经细胞具有特异性，并介导神经分化特异性的激活素信号传导。
