Abstract：
CONCLUSIONS: ARID-HMG DNA binding protein, AtHMGB15, regulates pollen development and pollen germination in Arabidopsis. Previous studies have shown that ARID-HMG DNA binding protein, AtHMGB15 regulate pollen development and pollen germination in Arabidopsis. Here, we performed transcriptome and cytological studies to understand the role of AtHMGB15 in regulating pollen wall morphology and the pollen tube germination rate. Our result showed abnormal vacuolization in the tapetal cells during anther maturation and prolonged PCD in AtHMGB15 loss-of-function mutant. The tapetum has the ability to perform both secretory and biosynthetic activities critical for pollen maturation and pollen viability. Interestingly, expression of PCD executer genes CEP1, MC9 and RNS3 were significant down-regulation of in athmgb15-4. The growth of pollen tubes is regulated by the actin cytoskeleton dynamics. To address the defect in pollen tube growth of athmgb15, we monitored the actin network in growing pollen tubes of wildtype and athmgb15-4 using Rhodamine-phalloidin fluorescence. Our results indicate a highly fragmented actin distribution in athmgb15-4 pollen tubes with a lesser number of long actin fibers and significantly low f-actin concentration at the apex. q-RTPCR further indicates significant downy-regulation of actin regulatory proteins VLN2 and PRF4. Collectively, our results suggest that AtHMGB15 being a nuclear architectural protein orchestrates high-order chromatin organization to promote the transcription of genes responsible for pollen development and pollen germination.
摘要：
结论：ARID-HMGDNA结合蛋白，AtHMGB15调节拟南芥花粉发育和花粉萌发。先前的研究表明，ARID-HMGDNA结合蛋白，AtHMGB15调控拟南芥花粉发育和花粉萌发。这里,我们进行了转录组和细胞学研究，以了解AtHMGB15在调节花粉壁形态和花粉管发芽率中的作用。我们的结果表明，在AtHMGB15功能丧失突变体中，花药成熟过程中绒毡层细胞空泡化异常，PCD延长。绒毡层具有执行对花粉成熟和花粉活力至关重要的分泌和生物合成活性的能力。有趣的是,PCD执行者基因CEP1、MC9和RNS3的表达显著下调。花粉管的生长受肌动蛋白细胞骨架动力学的调节。为了解决athmgb15花粉管生长的缺陷，我们使用罗丹明-连环蛋白荧光监测了野生型和athmgb15-4花粉管中的肌动蛋白网络。我们的结果表明，在athmgb15-4花粉管中，肌动蛋白分布高度分散，长肌动蛋白纤维数量较少，并且顶端的f-肌动蛋白浓度明显较低。q-RTPCR进一步表明肌动蛋白调节蛋白VLN2和PRF4的显著下调。总的来说，我们的结果表明，AtHMGB15是一种核结构蛋白，可协调高阶染色质组织，以促进负责花粉发育和花粉萌发的基因的转录。
