Interplay between SCARECROW, GA and LIKE HETEROCHROMATIN PROTEIN 1 in ground tissue patterning in the Arabidopsis root.
Interplay between SCARECROW, GA and LIKE HETEROCHROMATIN PROTEIN 1 in ground tissue patterning in the Arabidopsis root.
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DOI：
10.1111/j.1365-313x.2009.03839.x
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发表时间：
2009-06
期刊：
影响因子：
--
通讯作者：
Benfey PN
中科院分区：
文献类型：
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作者：
Cui H;Benfey PN
调节细胞分裂对于多细胞生物体的发育至关重要。在拟南芥根中，SCARECROW（SCR）是第一次细胞分裂所必需的，但抑制随后的纵向不对称细胞分裂，产生两种细胞类型的基本组织-皮层和内皮。为了阐明SCR在基础组织模式中的作用的分子基础，我们使用酵母双杂交方法筛选SCR相互作用蛋白。鉴定了许多推定的SCR相互作用蛋白质，其中包括异染色质蛋白质1（LHP 1）。在Ihp 1突变体，第二纵向不对称细胞分裂发生在地面组织早于野生型植物。与scr突变体相似，这种早熟的中皮层表型受到植物激素赤霉素（GA）的抑制。我们提供的证据表明，N-末端结构域的SCR是必需的SCR和LHP 1之间的相互作用，以及与其他相互作用的合作伙伴，这个域是必不可少的不对称细胞分裂的镇压。与GA在皮质增殖中的作用一致，关键GA信号传导组分的突变体早熟地产生中间皮质。有趣的是，我们发现细长（间谍）突变体具有类似的中皮层表型。由于SPY同源物在动物中与组蛋白脱乙酰酶发生物理相互作用，我们研究了组蛋白脱乙酰化在中皮层形成中的作用。我们发现，组蛋白脱乙酰酶活性的抑制导致过早的中皮层形成在野生型根。总之，这些结果表明，表观遗传调节可能是皮质细胞增殖中SCR和GA活性的共同基础。
Regulated cell division is critical for the development of multi-cellular organisms. In the Arabidopsis root, SCARECROW (SCR) is required for the first cell division, but represses the subsequent, longitudinal asymmetric cell divisions that generate the two cell types of the ground tissue – cortex and endodermis. To elucidate the molecular basis of the role of SCR in ground tissue patterning, we screened for SCR-interacting proteins using the yeast two-hybrid method. A number of putative SCR-interacting proteins were identified, among them LIKE HETEROCHROMATIN PROTEIN 1 (LHP1). In Ihp1 mutants, a second longitudinal asymmetric cell division occurs in the ground tissue earlier than in wild-type plants. Similar to the scr mutant, this premature middle cortex phenotype is suppressed by the phytohormone gibberellin (GA). We provide evidence that the N-terminal domain of SCR is required for the interaction between SCR and LHP1 as well as with other interacting partners, and that this domain is essential for repression of asymmetric cell divisions. Consistent with a role for GA in cortex proliferation, mutants of key GA signaling components produce a middle cortex precociously. Intriguingly, we found that the spindly (spy) mutant has a similar middle cortex phenotype. As SPY homologs in animals physically interact with histone deacetylase, we examined the role of histone deacetylation in middle cortex formation. We show that inhibition of histone deacetylase activity causes premature middle cortex formation in wild-type roots. Together, these results suggest that epigenetic regulation is probably the common basis for SCR and GA activity in cortex cell proliferation.