肌动蛋白是多头绒泡菌细胞核骨架和染色体骨架的组成成分

自多头绒泡菌(Physarum polycephalum Schw.)的原质团中分离细胞核和染色体,分别经DNaseⅠ消化和2 mol/L NaCl抽提后制备成细胞核骨架和染色体骨架。以抗肌动蛋白的抗体作一抗、FITC标记的羊抗兔IgG抗体作二抗进行的间接免疫荧光实验结果显示,细胞核骨架和染色体骨架都分别与抗体呈阳性反应。间接免疫斑点印迹实验结果进一步证实,细胞核骨架和染色体骨架的蛋白质成分中存在与肌动蛋白抗体呈阳性显色反应的抗原。以抗肌动蛋白的抗体作一抗、金颗粒标记的蛋白A作二抗的间接免疫电镜实验结果表明,在实验组间期细胞核的核仁、集缩染色质和核基质以及中期染色体上都有很多金颗粒分布。上述结果证明,肌动蛋白是多头绒泡菌细胞核和染色体及其骨架的组成成分。     

HeLa细胞核和核骨架含有肌动蛋白

提取HeLa细胞核并制备核骨架标本,以抗肌动蛋白抗体为探针,采用SDS－PAGE、免疫荧光和免疫印迹等方法,对HeLa细胞细胞核和核骨架中的肌动蛋白进行了研究,并用鬼笔环肽荧光染色方法研究了其中的F－肌动蛋白。在荧光显微镜下观察到：代表肌动蛋白的特异性荧光分布在细胞核和核骨架中,说明肌支蛋白是细胞核和核骨架的固有成分;代表F－肌动蛋白的特异性荧光存在于细胞和核骨架中,说明细胞核和核骨架含有F－肌动蛋白。免疫印迹结果进一步肯定了细胞核和核骨架中肌动蛋白的存在。     

大麦细胞核及染色体肌球蛋白免疫细胞化学定位

对去除DNA、组蛋白和大部分非组蛋白的大麦(Hordeum vulgare)细胞核和染色体间接免疫荧光标记实验结果表明:抗肌球蛋白抗体的荧光标记弥散分布在整个细胞核和染色体上;进一步应用免疫胶体金技术分析肌球蛋白在细胞核和染色体的分布情况,发现在染色体中散布着大量的胶体金颗粒;间期细胞核中胶体金颗粒主要分布在核仁和染色质中。上述实验结果表明:肌球蛋白是细胞核及染色体非组蛋白组成成分。本文还对肌球蛋白在细胞核和染色体中的分布规律进行了讨论。     

肌动蛋白存在于蚕豆细胞核和染色体中

以兔抗肌动蛋白抗体为一抗,FTTC偶联的羊抗兔IgG抗体为二抗进行间接免疫荧光实验,观察到蚕豆(Vicia faba L.)根端分生组织中完整的细胞核和染色体均有明亮荧光。用抗肌动蛋白抗体和蛋白A-胶体金进行标记的免疫电镜实验结果表明,金颗粒分布在蚕豆细胞核中,集缩染色质和核仁中金颗粒较多。经DNaseI消化和2 mol/L NaCl处理得到去除DNA和组蛋白的细胞核和染色体。免疫荧光实验结果指出,去除DNA和组蛋白的细胞核和染色体与抗肌动蛋白抗体呈阳性反应。上述结果说明,肌动蛋白不仅存在于完整的蚕豆细胞核和染色体中,而且存在于去除DNA和组蛋白的蚕豆细胞核和染色体中。另外,用抗原肌球蛋白抗体所做的免疫荧光标记结果表明,原肌球蛋白也存在于蚕豆细胞核和染色体中。对高等植物细胞核和染色体以及核骨架和染色体骨架是否含有肌动蛋白等问题进行了讨论。     

F—肌动蛋白是蒜根端分生组织细胞核和染色体的组成成分

以兔抗鸡肌动蛋白抗体为一抗、ＦＩＴＣ羊抗兔ＩｇＧ抗体为二抗进行间接免疫荧光标记实验,观察到蒜（ＡｌｉｕｍｓａｔｉｖｕｍＬ．）根端分生组织细胞核和染色体均发出明亮的黄绿色荧光,说明其中含有肌动蛋白。经ＴＲＩＴＣ鬼笔环肽标记后,完整的间期细胞、游离的间期细胞核、前期和中期染色体以及末期子细胞核均发出较强的红色荧光,而固定前用细胞松弛素Ｄ处理的根端分生组织细胞的荧光明显减弱或没有荧光,这些结果说明细胞核和染色体中存在着Ｆ肌动蛋白。抗肌动蛋白抗体和鬼笔环肽双标记实验结果指出,同一细胞核和染色体,在ＦＩＴＣ的激发光波长下发出代表总肌动蛋白的黄绿色的ＦＩＴＣ型荧光,在ＴＲＩＴＣ的激发光波长下则发出代表Ｆ肌动蛋白的红色的ＴＲＩＴＣ型荧光,两类荧光的分布是一致的。上述结果进一步证明Ｆ肌动蛋白是细胞核和染色体的组成成分,并说明Ｆ肌动蛋白可能是细胞核和染色体中肌动蛋白的主要存在方式。     

Cofilin-1在细胞核中的功能研究进展

Cofilin-1是一种肌动蛋白结合蛋白,主要通过切割肌动蛋白丝对细胞骨架进行动态重组,维系细胞内多种分子事件的有序进行。近年来,随着肌动蛋白在细胞核内的功能被逐步揭示,Cofilin-1作为肌动蛋白丝的关键调节因子之一,其在细胞核中的功能受到了广泛关注。该文通过系统阐述Cofilin-1在细胞核中的功能,如介导肌动蛋白入核,参与调控细胞核形状、染色体组织、基因转录、DNA损伤修复和细胞凋亡等,以期为深入研究Cofilin-1及其相关功能分子探索新的发展方向。     

紫鸭跖草花粉母细胞减数分裂细胞核和染色体含有F—肌动蛋白

肌动蛋白间接免疫荧光标记实验观察到紫鸭跖草花粉母细胞减数分裂前期Ⅰ细胞核,中期┘染色体,二分体和四分体均发现较明亮的黄绿色荧光,说明其中含有肌动蛋白。经ＴＲＩＴ－Ｃ鬼等环肽荧光标记后,减数分裂前Ⅰ细胞核,二分枝及中期Ⅰ染色体均发现较明亮的红色荧光;ＣＤ处理后细胞核和染色体的荧光明显减弱或没有荧光,说明其中存在Ｆ－肌动蛋白。     

肌动蛋白存在于车蝗精母细胞核和染色体中

以兔抗肌动蛋白抗体为一抗,FITC偶联的羊抗兔IgG抗体为二抗进行间接免疫荧光实验,观察到车蝗（Oedaleus asiaticus）精母细胞核及减数分裂Ⅰ细线期、终变期、减数分裂Ⅱ中期染色体上均发出明亮的黄经发色荧光,说明其中含有肌动蛋白。本文结果证明肌动蛋白是车蝗减数分裂细胞核和染色体的组成成分。     

百合花粉母细胞核骨架的超微结构观察

参照动物细胞核骨架的研究方法,用整装电镜技术和DGD包埋-去包埋技术研究了选择性抽提的和完整的百合(Lilium davidii var. willmottiae (Wilson) Roffill)花粉母细胞。结果表明,住减数分裂前期Ⅰ,百合花粉母细胞核内存在一个精细的非染色质纤维——核骨架。该网络由5～15nm的纤维交织而成,广泛地分布于细胞核内。这些核骨架有的分布于染色体间,有的分布于染色体周围,并与染色体和核仁相连。随着减数分裂时间的推移,染色体(质)间核骨架纤维逐渐减少,染色体(质)周围的核骨架纤维逐渐增多,并与染色体内部的纤维结构相连,表明核骨架一方面为染色体拓扑变化提供一个空间支架,另一方面也可能参与了染色体骨架的构建。     

肌动蛋白是扁绒泡菌Physarum compressum原质团细胞核核骨架成分

本研究以2mol/L NaCl或3, 5-二碘水杨酸锂（Lis）抽提扁绒泡菌Physarum compressum原质团细胞核,对残余蛋白进行电泳及肌动蛋白免疫印迹分析。结果表明单独用Lis抽提细胞核不能有效去除组蛋白,用2mol/L NaCl则可有效去除组蛋白,免疫印迹实验表明核骨架中存在着可以有效对抗2mol/L NaCl的肌动蛋白。     

Actin is a Constituent of the Nuclear Matrix and Chromosome Scaffold in Physarum poly cephalum

Nuclear matrices and chromosome scaffolds were obtained by digesting and extracting, respectively with DNase Ⅰ and 2 mol/L NaC1, the nuclei and chromosomes isolated from the plasmedia of Physarum polycephalum Schw. The results of the indirect immunofluorescence of tacit antiactin antibody as immunomarker indicated that the nuclear matrices and chromosome scaffolds both had positive reaction with the antibody. The results of the indirect immunodotting experiment further verified the presence of actin antibody in their constituent. Protein A-colloidal gold immunoelectron microscopy technique revealed that gold particles were distributed in the interphase nuclei and metaphase chromosomes. The above results showed that actin is a constituent of the nuclear matrix and chromosome scaffold of P. polycephalum.     

The presence of actin in nuclei: a critical appraisal.

To assess the significance of actin associations with nuclei, we have examined Amoeba proteus nuclei for the presence of labeled actin under a variety of circumstances without (in most instances) isolating nuclei or breaking up cytoplasms prior to the extraction of proteins.We first established that: the 42,000 dalton proteins (presumed to be actin) present in cytoplasm and non-isolated nuclei are identical electrophoretically; the putative actin of amebas has the same size and almost the same isoelectric point as rat muscle actin; and the peptide “fingerprints” of putative ameba actin and rat actin are very similar after tryptic digestion. We therefore concluded that the 42,000 dalton protein of ameba is actin.We determined that: the concentrations of actin in the cytoplasm and nucleus of amebas are the same; actin is readily lost from nuclei that are released from lysed cells; shortly after a ³⁵S-labeled nucleus is transplanted into unlabeled cytoplasm, or an unlabeled nucleus is transplanted into ³⁵S-labeled cytoplasm, the concentration of ³⁵S-actin in nucleus and cytoplasm is the same; and when cells containing ³⁵S-actin are subjected to long chase periods on unlabeled food, the concentrations of ³⁵S-actin in nucleus and cytoplasm fall in parallel. These observations taken together suggest that actin is not tightly associated with nuclei. Rather, actin may associate with nuclei for the trivial reason that the nuclear envelope is no barrier to free movement of that protein between the two compartments.We conclude that the mere presence of actin in nuclei is insufficient grounds for assuming that it has any role in nuclear functions, such as, for example, chromosome condensation.     

Lamin A/C and polymeric actin in genome organization

In this work, we have studied the structural and functional linkage between lamin A/C, nuclear actin, and organization of chromosome territories (CTs) in mammary carcinoma MCF-7 cells. Selective down-regulation of lamin A/C expression led to disruption of the lamin A/C perinuclear layer and disorganization of lamin-bound emerin complexes at the inner nuclear membrane. The silencing of lamin A/C expression resulted in a decrease in the volume and surface area of chromosome territories, especially in chromosomes with high heterochromatin content. Inhibition of actin polymerization led to relaxation of the structure of chromosome territories, and an increase in the volumes and surface areas of the chromosome territories of human chromosomes 1, 2 and 13. The results show an important role of polymeric actin in the organization of the nuclei and the chromosome territories.     

大鼠甲状腺促性腺激素释放激素受体的免疫组织化学及原位杂交研究

目的 探讨大鼠甲状腺中是否存在促性腺激素释放激素受体（GnRH-R)及其细胞定位,方法 收集15例雄性SD大鼠甲状腺,分别制成石蜡切片和冰冻切片,采用免疫组织化学ABC法和原位杂交技术。确定GnRH-R在其中的表达与定位。结果 大鼠甲状腺中,GnRH-R呈较强的免疫反应阳性,阳性物质分布在胞持,胞核呈阴性,原位杂交也检测到较强的GnRH-RmRNA阳性杂交信号,亦分布在胞质,胞核未见表达,结论 大鼠甲状腺可能自身合成GnRH-R。由此推断GnRH可能参与大鼠甲总而言之 腺功能的调节。     

THE ROLE OF F-ACTIN DURING FERTILIZATION IN THE RED ALGA AGLAOTHAMNION OOSUMIENSE (RHODOPHYTA)

The actin cytoskeletons in spermatia and trichogynes of Aglaothamnion oosumiense Itono were studied using fluorescein isothiocyanate (FITC) conjugated phalloidin and the cytoskeletal inhibitors, potassium iodide (KI), cytochalasin-B, and latrunculin-A. Microfilaments were localized to the distal ends of elongated spermatia and trichogynes and were more prominent in the trichogyne before spermatium binding. The actin cytoskeleton in spermatia and trichogynes was disrupted by treatment with 0.6 M KI, 100 μM cytochalasin-B, or 10 μM latrunculin-A. The actin cytoskeleton in trichogynes recovered within 24 h of removal from the inhibitor, but no recovery was observed in spermatia. Spermatial nuclei entered mitosis as soon as spermatia attached to the trichogyne. The greatest percentage (50%– 60%) of spermatia having completed mitosis was obtained at 60 min after spermatial binding to trichogynes. During mitosis, actin accumulated in the center of the spermatium, thereby separating the two daughter nuclei. Cytoskeletal inhibitors did not affect initial binding of spermatia to trichogynes but did block subsequent stages of fertilization, including spermatial mitosis and gamete fusion. The accumulation of cellulose or β-linked polysaccharide on the spermatial surface was also blocked by treatment with actin inhibitors. Exposure of the trichogyne to actin inhibitors after gamete fusion caused spermatial nuclei in trichogynes to stop moving and to condense. These results suggest that the microfilaments involved in nuclear division, cellulose deposition into the spermatial wall, gamete fusion, and migration of spermatial nuclei in trichogynes during fertilization in Aglaothamnion oosumiense.     

烟草花粉母细胞减数分裂前期Ⅰ肌动蛋白的免疫细胞化学定位(简报)

肌动蛋白是一种主要的收缩蛋白,在肌肉细胞中是广泛存在的,而在非肌肉细胞中,如在藻类细胞以及高等植物的根尖细胞、表皮细胞中,也存有肌动蛋白。在花粉萌发过程中,肌动蛋白丝集聚成束,对于花粉管的形成和受精过程有着重要作用。但已有的工作,多数限于动物细胞和植物体细胞中,关于高等植物的生殖细胞中的报道则比较少见。