Cytoskeletal organisation and modification during pollen tube arrival, gamete delivery and fertilisation in Plumbago zeylanica
Cytoskeletal organisation and modification during pollen tube arrival, gamete delivery and fertilisation in Plumbago zeylanica
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DOI：
10.1017/s0967199400001404
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发表时间：
1993-05-01
期刊：
影响因子：
1.7
通讯作者：
Cresti, Mauro
中科院分区：
文献类型：
--
作者：
Huang, Bing-Quan;Pierson, Elisabeth S.;Cresti, Mauro
在花粉管进入胚囊之前、期间和之后，研究了分离的白花苜蓿胚囊和卵细胞的细胞骨架组织，以确定微管和肌动蛋白丝在受精过程中的潜在参与。使用Hoechst 33258对材料进行单次和三次染色以定位DNA，使用异硫氰酸荧光素（FITC）标记的抗α微管蛋白检测微管，使用罗丹明-phalloidin观察f -肌动蛋白。未受精卵细胞中的微管纵向排列在微孔和中外侧区域，在丝状器附近聚集成束。在卵细胞的核周细胞质中，微管或多或少地随机排列。f -肌动蛋白束在卵细胞的合点细胞质中形成纵向排列的网状结构。在中央细胞，微管和f -肌动蛋白沿空泡链分布，在核周区和细胞外周也很明显。在花粉管穿透过程中，靠近花粉管通道的稀疏微管束可能在传递点的雄性配子周围形成明显的微管“导管”。肌动蛋白聚集体在花粉管通道附近和精子细胞的传递部位组织起来。随后，肌动蛋白聚集在卵细胞和中心细胞之间的细胞间区域形成“冠状”结构，配子融合发生在这里。冠状体可能在保持卵子和中心细胞的紧密接近，帮助两个精子细胞移动并与目标细胞结合方面发挥作用。细胞骨架可能还参与了使卵细胞和中央细胞的两个核在配子融合位点相互靠近，并将两个精子核运送到与其各自的雌性核对齐的过程。细胞骨架在胚胎发生早期重组。
The cytoskeletal organisation of the isolated embryo sac and egg cells of Plumbago zeylanica was examined before, during and after pollen tube penetration into the embryo sac to determine the potential involvement of microtubules and actin filaments in fertilisation. Material was singly and triply stained using Hoechst 33258 to localise DNA, fluorescein isothiocyanate (FITC)-labelled anti-alpha-tubulin to detect microtubules and rhodamine-phalloidin to visualise F-actin. Microtubules in the unfertilised egg cell are longitudinally aligned in the micropylar and mid-lateral areas, aggregating into bundles near the filiform apparatus. In the perinuclear cytoplasm of the egg cell, microtubules become more or less randomly aligned. F-actin bundles form a longitudinally aligned mesh in the chalazal cytoplasm of the egg cell. In the central cell, microtubules and F-actin are distributed along transvacuolar strands and are also evident in the perinuclear region and at the periphery of the cell. During pollen tube penetration, sparse microtubule bundles near the pathway of the pollen tube may form an apparent microtubular 'conduit' surrounding the male gametes at the delivery site. Actin aggregates become organised near the pathway of the pollen tube and at the delivery site of the sperm cells. Subsequently, actin aggregates form a 'corona' structure in the intercellular region between the egg and central cell where gametic fusion occurs. The corona may have a role in maintaining the close proximity of the egg and central cell and helping the two sperm cells move and bind to their target cells. The cytoskeleton may also be involved in causing the two nuclei of the egg and central cell to approach one another at the site of gametic fusion and transporting the two sperm nuclei into alignment with their respective female nucleus. The cytoskeleton is reorganised during early embryogenesis.