Mahony D, Weis F M, Massagué J, Gurdon J B
Wellcome/CRC Institute, Tennis Court Road, Cambridge, CB2 1QR, UK.
Mech Dev. 1998 Jul;75(1-2):95-105. doi: 10.1016/s0925-4773(98)00092-6.
We have previously cloned a type I serine/threonine kinase receptor from Xenopus, namely XTrR-I. We show here that XTrR-I is able to bind and mediate the activity of TGFbeta1, but is unable to mediate response to activin or BMP-4. We have made a truncated receptor construct that can act as a dominant negative mutant receptor, and this can block the activity of TGFbeta2 but not that of activin. Overexpression of either the full-length or truncated receptor has a drastic effect on mesoderm differentiation. The truncated receptor inhibits expression of notochord and muscle in mesodermalised animal caps, while the full-length receptor greatly increases the amount of notochord. In addition, the truncated receptor blocks the axis duplicating activity of both siamois and Xwnt8. We conclude that XTrR-I is involved in mediating a dorsalising activity important for mesoderm differentiation.
我们之前从非洲爪蟾中克隆出了一种I型丝氨酸/苏氨酸激酶受体，即XTrR-I。我们在此表明，XTrR-I能够结合并介导TGFβ1的活性，但无法介导对激活素或BMP-4的反应。我们构建了一种截短的受体构建体，它可以作为显性负性突变受体，并且能够阻断TGFβ2的活性，但不能阻断激活素的活性。全长或截短受体的过表达对中胚层分化有显著影响。截短受体抑制中胚层化动物帽中脊索和肌肉的表达，而全长受体则大大增加脊索的数量。此外，截短受体阻断了暹罗蛋白和Xwnt8的轴重复活性。我们得出结论，XTrR-I参与介导对中胚层分化重要的背化活性。
