Proliferation and cell fate establishment during Arabidopsis male gametogenesis depends on the Retinoblastoma protein
Proliferation and cell fate establishment during Arabidopsis male gametogenesis depends on the Retinoblastoma protein
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DOI：
10.1073/pnas.0810992106
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发表时间：
2009-04-28
影响因子：
11.1
通讯作者：
Berger, Frederic
中科院分区：
文献类型：
--
作者：
Chen, Zhong;Hafidh, Said;Berger, Frederic
视网膜母细胞瘤（Rb）蛋白是细胞增殖的保守阻遏物。在动物和植物中，Rb蛋白的失调导致细胞过度增殖并在不同程度上干扰细胞分化。然而，Rb蛋白丢失的主要发育影响仍不清楚。在这项研究中，我们研究了直接后果Rb蛋白基因敲除拟南芥雄性生殖细胞使用细胞学和分子标记。拟南芥生殖系起源于小孢子的不均等分裂，产生一个小的生殖细胞和一个大的终末分化的营养细胞。生殖细胞的一次分裂产生2个精细胞。我们观察到，Rb蛋白的损失并没有对小孢子分裂产生重大影响，但会导致有限的过度增殖的营养细胞，并在较小程度上，精子细胞。此外，细胞的命运是扰动的一部分Rb缺陷的营养细胞。这些缺陷通过阻止细胞周期蛋白依赖性激酶A1的下调引起的细胞增殖来挽救。我们的研究结果表明，过度增殖引起的Rb蛋白的损失，防止或延迟植物雄配子发生过程中的细胞决定，命运决定和细胞增殖之间的直接联系提供了进一步的证据。
The Retinoblastoma (Rb) protein is a conserved repressor of cell proliferation. In animals and plants, deregulation of Rb protein causes hyperproliferation and perturbs cell differentiation to various degrees. However, the primary developmental impact of the loss of Rb protein has remained unclear. In this study we investigated the direct consequences of Rb protein knockout in the Arabidopsis male germline using cytological and molecular markers. The Arabidopsis germ line derives from the unequal division of the microspore, producing a small germ cell and a large terminally differentiated vegetative cell. A single division of the germ cell produces the 2 sperm cells. We observed that the loss of Rb protein does not have a major impact on microspore division but causes limited hyperproliferation of the vegetative cell and, to a lesser degree, of the sperm cells. In addition, cell fate is perturbed in a fraction of Rb-defective vegetative cells. These defects are rescued by preventing cell proliferation arising from down-regulation of cyclin-dependent kinase A1. Our results indicate that hyperproliferation caused by the loss of Rb protein prevents or delays cell determination during plant male gametogenesis, providing further evidence for a direct link between fate determination and cell proliferation.