植物rRNA基因组织模式的荧光原位杂交比较分析  

Comparison of the Organization Pattern of the rRNA Gene in Plants Using Fluorescence in situ Hybridization

作　　者：佘朝文[1,2,3] 蒋向辉[1,2,3] 宋运淳[4] 

机构地区：[1]怀化学院生命科学系,湖南怀化418008 [2]怀化学院民族药用植物资源研究与利用湖南省重点实验室,湖南怀化418008 [3]怀化学院湘西药用植物与民族植物学湖南省高校重点实验室,湖南怀化418008 [4]武汉大学杂交水稻国家重点实验室,武汉430072

出　　处：《植物科学学报》2012年第2期169-177,共9页Plant Science Journal

基　　金：国家自然科学基金项目(39870423)~~

摘　　要：采用荧光原位杂交技术,对分属5个科的10种植物的分生细胞的18S-25S rRNA基因(45S rDNA)的组织模式进行了比较分析。45S rDNA探针在所有供试植物的间期核都产生了两种杂交信号:荧光强、位于核仁周边的纽和荧光较弱分布于核仁内的点,表明不同植物间期核的rDNA染色质的组织模式相似。在每种植物的部分间期细胞都观察到点与纽相连或从纽发出的情况,而且点的数目越多纽就变得越小,点的有无和数目的多少与细胞的活性呈正相关。这些事实表明,纽代表了处于凝缩状态的非活性的rDNA染色质,点是由纽解凝缩而来,rDNA异染色质解凝缩形成点是植物rRNA基因活跃转录的细胞学表现,在同一物种中点的多少代表了间期核rDNA转录活性的强弱。我们的结果支持点是核仁内活性rRNA基因组织的结构单位及rRNA合成发生地点的推论。我们的结果还显示,不同植物间期核的rDNA染色质的组织也存在一些差异,其中核仁内点的最大数目有较大的不同。在所有供试植物的有丝分裂前中期细胞,45S rDNA探针在rDNA位点都产生了松散的信号块和许多点,表明植物的rDNA位点在有丝分裂前中期还有较活跃的转录。The organization patterns of 18S-25S rRNA gene（45S rDNA） in the meristematic cells of ten plants belonging to five families were comparatively analyzed using fluorescence in situ hybridization（FISH）.The 45S rDNA probe produced two types of signals in the interphase nuclei of all tested species： strongly fluorescing perinucleolar knobs and weakly fluorescing intranucleolar spots,indicating the existence of similar organization patterns of rDNA chromatin at interphase in higher plants.The spots associated with or emanating from the knobs were observed in a portion of the interphase nuclei in each tested species.It was obvious that the more spots produced,the smaller the knobs became,and the number of spots was positively correlated with the activity of the cell.These findings indicated that the spots resulted from the decondensation of knobs,the decondensation of rDNA heterochromatin was the cytogenetic ma-nifestation of active rRNA gene transcription,and the number of spots represented the degree of transcription activity of rRNA gene at interphase.Our results supported the speculation that these spots were the structural units in the organization of active ribosomal genes and the sites that rRNA synthesis took place.Our results also revealed some differences in the organization of rDNA chromatin at interphase among species.The maximal number of spots in the nucleolus differed considerably among the tested species.In prometaphase cells of each tested species,the rDNA sites displayed incompact signal blocks and many spots by FISH with rDNA probe,indicating an active rDNA transcription during prometaphase.

关 键 词：RRNA基因 组织模式 植物间期核 荧光原位杂交 

分 类 号：Q943[生物学—植物学]