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The cell and tissues
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
In prophase the nuclear membrane breaks down, the nucleus disappears and the long strands of chromatin condense (become densely coiled) to form the familiar chromosome shapes (remember that the cell has already made duplicate copies of its DNA ready for the two daughter cells). The centrioles, discussed earlier, produce guiding filaments that create a cage-like structure called the spindle. During prophase, the chromosomes begin to migrate towards the middle of the cell.
Manipulating the Intracellular Trafficking of Nucleic Acids
Published in Kenneth L. Brigham, Gene Therapy for Diseases of the Lung, 2020
Kathleen E. B Meyer, Lisa S. Uyechi, Francis C. Szoka
The nucleus is bounded by the nuclear envelope, which encloses chromatin and the machinery necessary for gene transcription. The nucleus is a dynamic structure, which disassembles at the onset of mitosis and reassembles during telophase. The envelope consists of two membrane bilayers, posing a considerable hydrophobic barrier to macromolecular transport (Fig. 3). The outer nuclear membrane is continuous with the endoplasmic reticulum, and with the inner nuclear membrane forms a perinuclear space that is continuous with the endoplasmic reticulum lumen (82,83). The inner nuclear membrane is supported internally by the nuclear lamina, a network of lamin proteins that lines the inner side of the envelope (82). The lamina also is thought to provide attachment sites for chromatin (84-86). The very interior of the nucleus is a network of DNA, RNA, and proteins. It is the active transcriptions sites that are the targets of gene delivery.
Cell structure, function and adaptation
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
The nucleus is not an inert structure cut off from the rest of the cell (Figure 2.1). The nuclear membrane is constantly crossed by factors that regulate the expression of genes and may repair DNA damage as soon as it occurs.
The Role of Neutrophil Extracellular Traps in the Ocular System
Published in Current Eye Research, 2022
Yingsi Li, Luoying Xie, Wenjing Song, Meiting Huang, Yu Cheng, Shudi Chen, Yuan Gao, Xiaoming Yan
Conventional suicidal NETosis was initially found after PMA-induced NET formation.1 The activation of protein kinase C (PKC) by PMA results in a high level of cytoplasmic Ca2+via release from the endoplasmic reticulum. Due to Ca2+ influx, the Raf-MEK-ERK pathway is activated via the activation of NOX and the upregulation of anti-apoptotic proteins.19,20 The next important step is the generation of ROS, which are produced via a NOX-dependent or mitochondrial pathway.21,22 An ROS burst induces NE and MPO migration to the nucleus to collectively degrade histones and promote chromatin decondensation.21,23 Protein-arginine deiminase type 4 (PAD4) is a key nuclear enzyme in NET formation that drives histone 3 citrullination, and it is activated by Ca2+ influx.19,24 Rupture of the nuclear membrane allows the combination of granular proteins and DNA to form NETs, which are extruded into the extracellular compartment as the cell membrane disintegrates.20,25 This process ends with NET release and cell death and is also known as lytic NETosis (Figure 1).
Cancer vaccines as a targeted immunotherapy approach for breast cancer: an update of clinical evidence
Published in Expert Review of Vaccines, 2022
Maryam Abbaspour, Vajihe Akbari
DNA vaccines are bacterial plasmids generated to deliver TA-encoding genes that create or enhance an adaptive immune response to TA-bearing tumor cells [120]. The main strength of DNA vaccines is that they can activate CD4 and CD8 T cells as well as indirectly the humoral immunity by providing antigens encoded by MHC class I and class II [121]. So far, there are no approved DNA vaccines for use in humans and they are undervaluation in phase I or II clinical studies. To enhance efficient immune responses of DNA vaccines, a plasmid delivery system was optimized and they were often developed in combination with other vaccines platforms therapies. The most common methods used to increase transfection efficiencies, such as localized delivery system, electroporation, sonication, and gene gun, can overcome the barriers (intra- or extracellular) to DNA transfer [122,123]. To induce protein synthesis, DNA requires passing through the nuclear membrane. DNA vaccines can integrate into the host genome leading to insertional mutagenesis, chromosomal instability, and oncogenic transformation. The expression of DNA-encoded proteins can be taken place over months to years, depending on vector [124].
Response characteristics and optimization of electroporation: simulation based on finite element method
Published in Electromagnetic Biology and Medicine, 2021
Cheng Zhou, Zeyao Yan, Kefu Liu
The spatial TMV distribution in the nuclear membrane is similar to that in the cell membrane (Figure 5b). TMV will be in the form of a cosine distribution before electroporation and then decrease at the poles (points 3/4/9/10). The differences between the TMV in the nuclear membrane and the cell membrane are manifest at much higher electric field strengths and there is a smaller decrease in nuclear TMV after electroporation. Furthermore, the pore density in nuclear membrane (~Figures 6). However, when the electric field strength is higher than the threshold value, the maximum pore density in the nuclear membrane (~