Snoek G T, Koster C H, de Laat S W, Heideveld M, Durston A J, van Zoelen E J
Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht.
Exp Cell Res. 1990 Apr;187(2):203-10. doi: 10.1016/0014-4827(90)90083-m.
The Xenopus laevis XTC cell line has been analyzed for the production of polypeptide growth factors and mesoderm-inducing activity. By the use of specific biological assays, it is shown that XTC cells produce a growth factor functionally related to the platelet-derived growth factor (PDGF) and two transforming growth factor (TGF) beta-like activities. Mesoderm-inducing activity, as measured on X. laevis ectodermal explants from stage 10 embryos, was found to coelute on a Bio-Gel P-100 column with one of the TGF beta-like activities at an apparent molecular weight of 6-10 kDa. Analysis of the DNA content from XTC cells by flow cytometry demonstrated that the cell line is heterogeneous and consists of both tetraploid and diploid cells. Cloning of the XTC cells and selecting single-cell colonies on the basis of their ability to grow in soft agar resulted in the isolation of several homogeneous, morphologically different clonal derivatives. Analysis of conditioned medium from these clonal derivatives showed that only one of them, the only diploid line among six investigated, produced a strong heat- and acid-stable mesoderm-inducing activity that induced notochord and muscle formation in stage 10 X. laevis ectodermal explants. The relation between this activity and a recently described TGF beta-like mesoderm-inducing factor obtained from XTC-conditioned medium will be discussed. In conclusion, a clonal cell line derived from X. laevis XTC cells which provides a good source for further characterization of mesoderm-inducing factors has been established.
对非洲爪蟾XTC细胞系进行了多肽生长因子产生及中胚层诱导活性方面的分析。通过特定生物学检测表明，XTC细胞产生一种在功能上与血小板衍生生长因子（PDGF）相关的生长因子以及两种转化生长因子（TGF）β样活性物质。以10期胚胎的非洲爪蟾外胚层植块所测得的中胚层诱导活性，在Bio-Gel P - 100柱上与一种TGFβ样活性物质共洗脱，其表观分子量为6 - 10 kDa。通过流式细胞术分析XTC细胞的DNA含量表明，该细胞系具有异质性，由四倍体细胞和二倍体细胞组成。对XTC细胞进行克隆，并基于其在软琼脂中生长的能力选择单细胞集落，从而分离出几种形态不同的均一克隆衍生物。对这些克隆衍生物的条件培养基进行分析表明，在所研究的六个克隆中，只有其中之一（唯一的二倍体株系）产生了一种强烈的热稳定和酸稳定的中胚层诱导活性，该活性可诱导10期非洲爪蟾外胚层植块形成脊索和肌肉。将讨论这种活性与最近从XTC条件培养基中获得的一种TGFβ样中胚层诱导因子之间的关系。总之，已建立了一种源自非洲爪蟾XTC细胞的克隆细胞系，它为进一步鉴定中胚层诱导因子提供了良好来源。
