The SIDECAR POLLEN gene encodes a microspore-specific LOB/AS2 domain protein required for the correct timing and orientation of asymmetric cell division
The SIDECAR POLLEN gene encodes a microspore-specific LOB/AS2 domain protein required for the correct timing and orientation of asymmetric cell division
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DOI：
10.1111/j.1365-313x.2010.04374.x
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发表时间：
2010-12-01
期刊：
影响因子：
7.2
通讯作者：
Park, Soon Ki
中科院分区：
文献类型：
--
作者：
Oh, Sung Aeong;Park, Keun Sang;Park, Soon Ki
植物细胞的构型和分化取决于不对称分裂和对称分裂的平衡.开花植物中雄配子体（花粉粒）的形成需要小孢子的不对称分裂，然后是生殖细胞的对称分裂，以产生三个高度分化的细胞：一个营养细胞和两个精细胞。在拟南芥的侧室花粉（SCP）突变体的小孢子的比例首先对称分裂，然后继续生产'四细胞'花粉与额外的营养细胞，然而，细节的SCP和身份的SCP基因的表型缺陷的时间和起源仍然模糊不清。原始的亚型SCP-1等位基因和T-DNA诱导的无效等位基因SCP-2的比较分析表明，在SCP的情况下，小孢子进行正常的核定位，但显示延迟进入有丝分裂，增加细胞扩张和改变核分裂的方向。我们鉴定了SCP基因编码一种雄性配子体特异性的侧向器官边界域/不对称叶2样（LBD/ASL）蛋白，该蛋白在小孢子核中以严格调控的阶段特异性方式表达。因此，我们的研究表明，雄配子体的正确模式取决于核LBD/ASL家族蛋白的活性，这是必不可少的不对称小孢子分裂的正确时机和方向。
P>Cellular patterning and differentiation in plants depend on the balance of asymmetric and symmetric divisions. Patterning of the male gametophyte (pollen grains) in flowering plants requires asymmetric division of the microspore followed by a symmetric division of the germ cell to produce three highly differentiated cells: a single vegetative cell and two sperm cells. In Arabidopsis sidecar pollen (scp) mutants a proportion of microspores first divide symmetrically, and then go on to produce 'four-celled' pollen with an extra vegetative cell; however, details of the timing and origin of phenotypic defects in scp and the identity of the SCP gene have remained obscure. Comparative analysis of the original hypomorphic scp-1 allele and a T-DNA-induced null allele, scp-2, revealed that in the absence of SCP, microspores undergo normal nuclear positioning, but show delayed entry into mitosis, increased cell expansion and alterations in the orientation of nuclear division. We identified the SCP gene to encode a male gametophyte-specific LATERAL ORGAN BOUNDARIES DOMAIN/ASYMMETRIC LEAVES 2-like (LBD/ASL) protein that is expressed in microspore nuclei in a tightly regulated phase-specific manner. Therefore, our study demonstrates that the correct patterning of male gametophyte depends on the activity of a nuclear LBD/ASL family protein that is essential for the correct timing and orientation of asymmetric microspore division.