The nuclear envelope protein KAKU4 determines the migration order of the vegetative nucleus and sperm cells in pollen tubes
The nuclear envelope protein KAKU4 determines the migration order of the vegetative nucleus and sperm cells in pollen tubes
复制标题
DOI：
10.1093/jxb/eraa367
复制
发表时间：
2020-10-22
影响因子：
6.9
通讯作者：
Hara-Nishimura, Ikuko
中科院分区：
文献类型：
--
作者：
Goto, Chieko;Tamura, Kentaro;Hara-Nishimura, Ikuko
KAKU4是核层的一种可能的组成蛋白，它调节拟南芥幼苗的核形态，但其生理意义尚不清楚。KAKU4在成熟的花粉粒中高度表达，每个花粉粒都有一个营养细胞和两个精子细胞。KAKU4蛋白在花粉粒和伸长花粉管的营养核膜上含量较高，而在精核的膜上含量较低。野生型花粉的营养核形状不规则。然而，KAKU4缺乏使它们变得更圆。花粉粒萌发后，营养核和精子细胞进入花粉管并沿着花粉管移动。在野生型中，90%的花粉管营养核在精子核之前，而在kaku4突变体中，只有大约一半的花粉管营养核在精子核之前。Kaku4花粉授粉后受精的竞争性低于野生型花粉。这些结果使我们推测，花粉粒营养细胞中的核形状影响着营养核和精子细胞在花粉管中的有序迁移。
A putative component protein of the nuclear lamina, KAKU4, modulates nuclear morphology in Arabidopsis thaliana seedlings, but its physiological significance is unknown. KAKU4 was highly expressed in mature pollen grains, each of which has a vegetative cell and two sperm cells. KAKU4 protein was highly abundant on the envelopes of vegetative nuclei and less abundant on the envelopes of sperm cell nuclei in pollen grains and elongating pollen tubes. Vegetative nuclei are irregularly shaped in wild-type pollen. However, KAKU4 deficiency caused them to become more spherical. After a pollen grain germinates, the vegetative nuclei and sperm cells enter and move along the pollen tube. In the wild type, the vegetative nucleus preceded the sperm cell nuclei in >90% of the pollen tubes, whereas, in kaku4 mutants, the vegetative nucleus preceded the sperm cell nuclei in only about half of the pollen tubes. kaku4 pollen was less competitive for fertilization than wild-type pollen after pollination. These results led us to hypothesize that the nuclear shape in vegetative cells of pollen grains affects the orderly migration of the vegetative nucleus and sperm cells in pollen tubes.