Preferential degradation of plastid DNA with preservation of mitochondrial DNA in the sperm cells ofPelargonium zonale during pollen development
Preferential degradation of plastid DNA with preservation of mitochondrial DNA in the sperm cells ofPelargonium zonale during pollen development
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天竺葵花粉发育过程中质体DNA优先降解并保留线粒体DNA
DOI：
10.1007/bf01288031
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发表时间：
1997
期刊：
影响因子：
2.9
通讯作者：
T. Kuroiwa
中科院分区：
文献类型：
--
作者：
N. Nagata;Sodmergen;C. Saito;A. Sakai;H. Kuroiwa;T. Kuroiwa
在本研究中，我们用4‘，6-二氨基-2-苯基吲哚(DAPI)染色后的荧光显微镜和用抗DNA抗体的免疫金电子显微镜研究了成熟花粉Pelargonium zonale精细胞中细胞器DNA的变化。用视频增强型显微光子计数系统(VIMPCS)定量检测不同发育阶段生殖细胞和精子细胞中DAPI染色的胞体核的荧光强度。结果表明，在花粉发育过程中，生殖细胞中每个质体的DNA含量逐渐增加，并在开花前5d达到最大值(约70T/质体；1T代表一粒T4噬菌体中的DNA含量)。然而，随后叶绿体的DNA含量下降到开花当天最大值的20%左右。此外，在萌发介质中培养6h后，质粒DNA含量进一步下降到最大值的4%。相反，每个线粒体的DNA含量在开花前后并没有显著下降。使用抗DNA抗体的免疫金电子显微镜也得到了类似的结果。在花粉成熟过程中，质体上的金颗粒密度下降，而线粒体上的标记密度保持相对恒定。每个生殖细胞或每对精细胞的质体和线粒体的数量没有显著变化，这表明每个生殖细胞或每对精细胞的DNA含量的下降不是由于质体分裂对DNA的分离造成的。这些结果表明，在精细胞OFP中，叶绿体DNA优先降解，而线粒体DNA被保存。Zonale。虽然受精前精细胞的胞质DNA含量下降，但精细胞胞质中残留的低DNA含量足以解释胞体INP的双亲遗传。Zonale。
SummaryIn the present study, we studied changes in organellar DNA in the sperm cells of maturing pollen ofPelargonium zonale, a plant typical to exhibit biparental inheritance, by fluorescence microscopy after staining with 4′,6-diamidino-2-phenylindole (DAPI) and by immunogold electron microscopy using anti-DNA antibody. Fluorescence intensities of DAPI-stained plastid nuclei in generative and sperm cells at various developmental stages were quantified with a video-intensified microscope photon counting system (VIMPCS). Results indicated that the amount of DNA per plastid in generative cells increased gradually during pollen development and reached a maximum value (about 70 T per plastid; 1 T represents the amount of DNA in a particle of T4 phage) in young sperm cells at 5 days before flowering. However, the DNA content of plastids was subsequently reduced to about 20% of the maximum value on the day of flowering. Moreover, the DNA content of the plastid further decreased to 4% of the maximum value when pollen grains were cultured for 6 h in germination medium. In contrast, the amount of DNA per mitochondrion did not decrease significantly around the flowering day. Similar results were also obtained by immunogold electron microscopy using anti-DNA antibody. The density of gold particles on plastids decreased during pollen maturation whereas labelling density on mitochondria remained relatively constant. The number of plastids and mitochondria per generative cell or per pair of sperm cells did not change significantly, indicating that the segregation of DNA by plastid division was not responsible for the decrease in the amount of DNA per plastid. These results indicate that the plastid DNA is preferentially degraded, but the mitochondrial DNA is preserved, in the sperm cells ofP. zonale. While the plastid DNA of the sperm cells decreased before fertilization, it was also suggested that the low DNA contents that remain in the plastids of the sperm cells are enough to account for the biparental inheritance of plastids inP. zonale.
海胆卵细胞质中小极性荧光团的皮秒旋转。
影响因子：
2.9
作者：
Periasamy,N;Armijo,M;Verkman,AS
通讯作者：
Verkman,AS