Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation.

Programmed cell death (PCD) plays a key role in developmental biology and in maintenance of the steady state in continuously renewing tissues. Currently, its existence is inferred mainly from gel electrophoresis of a pooled DNA extract as PCD was shown to be associated with DNA fragmentation. Based on this observation, we describe here the development of a method for the in situ visualization of PCD at the single-cell level, while preserving tissue architecture. Conventional histological sections, pretreated with protease, were nick end labeled with biotinylated poly dU, introduced by terminal deoxy-transferase, and then stained using avidin-conjugated peroxidase. The reaction is specific, only nuclei located at positions where PCD is expected are stained. The initial screening includes: small and large intestine, epidermis, lymphoid tissues, ovary, and other organs. A detailed analysis revealed that the process is initiated at the nuclear periphery, it is relatively short (1-3 h from initiation to cell elimination) and that PCD appears in tissues in clusters. The extent of tissue-PCD revealed by this method is considerably greater than apoptosis detected by nuclear morphology, and thus opens the way for a variety of studies.

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Apoptotic cell death at tooth eruption in rat molar observed by in situ labeling of nuclear DNA fragmentation.

Japanese Journal of Oral Biology ◽

10.2330/joralbiosci1965.37.488 ◽

1995 ◽

Vol 37 (6) ◽

pp. 488-492 ◽

Cited By ~ 4

Author(s):

Yoshihiro Abiko ◽

Hidetoshi Kanno ◽

Jiro Arai ◽

Michiko Nishimura ◽

Masato Saitoh ◽

...

Keyword(s):

Cell Death ◽

Dna Fragmentation ◽

Nuclear Dna ◽

Apoptotic Cell ◽

Tooth Eruption ◽

Apoptotic Cell Death ◽

Nuclear Dna Fragmentation ◽

Rat Molar

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Mechanisms of programmed cell death

Journal of Applied Biotechnology & Bioengineering ◽

10.15406/jabb.2019.06.00188 ◽

2019 ◽

Vol 6 (4) ◽

pp. 156-158

Author(s):

Abdu-Alhameed A Ali Azzwali ◽

Azab Elsayed Azab

Keyword(s):

Dna Damage ◽

Cell Death ◽

Programmed Cell Death ◽

Nuclear Dna ◽

Chromatin Condensation ◽

Cell Shrinkage ◽

Membrane Blebbing ◽

Development And Aging ◽

Nuclear Dna Fragmentation ◽

Dependent Pathway

The present review aims to spotlight on the mechanisms and stages of programmed cell death. Apoptosis, known as programmed cell death, is a homeostatic mechanism that generally occurs during development and aging in order to keep cells in tissue. It can also act as a protective mechanism, for example, in immune response or if cells are damaged by toxin agents or diseases. In cancer treatment, drugs and irradiation used in chemotherapy leads to DNA damage, which results in triggering apoptosis through the p53 dependent pathway in cancer treatment, drugs and irradiation used in chemotherapy leads to DNA damage, which results in triggering apoptosis through the p53 dependent pathway. Corticosteroids can cause apoptotic death in a number of cells. A number of changes in cell morphology are related to the different stages of apoptosis, which includes nuclear DNA fragmentation, cell shrinkage, chromatin condensation, membrane blebbing, and the formation of apoptotic bodies. There are three pathways for apoptosis, the intrinsic (mitochondrial) and extrinsic (death receptor) are the two major paths that are interlinked and that can effect one another. Conclusion: It can be concluded that apoptosis is a homeostatic mechanism that generally occurs during development and aging in order to keep cells in tissue. Drugs and irradiation used in chemotherapy leads to DNA damage, which results in triggering apoptosis through the p53 dependent pathway. The apoptosis, stages are includes nuclear DNA fragmentation, cell shrinkage, chromatin condensation, membrane blebbing, and the formation of apoptotic bodies. There are three pathways for apoptosis.

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Ca2+-dependent nuclease is involved in DNA degradation during the formation of the secretory cavity by programmed cell death in fruit of Citrus grandis ‘Tomentosa’

Journal of Experimental Botany ◽

10.1093/jxb/eraa199 ◽

2020 ◽

Vol 71 (16) ◽

pp. 4812-4827 ◽

Cited By ~ 1

Author(s):

Mei Bai ◽

Minjian Liang ◽

Bin Huai ◽

Han Gao ◽

Panpan Tong ◽

...

Keyword(s):

Cell Death ◽

In Situ Hybridization ◽

Programmed Cell Death ◽

Nuclear Dna ◽

Expression Patterns ◽

Citrus Fruit ◽

Dna Degradation ◽

Secretory Cavity ◽

Spatio Temporal

Abstract The secretory cavity is a typical structure in Citrus fruit and is formed by schizolysigeny. Previous reports have indicated that programmed cell death (PCD) is involved in the degradation of secretory cavity cells in the fruit, and that the spatio-temporal location of calcium is closely related to nuclear DNA degradation in this process; however, the molecular mechanisms underlying this Ca2+ regulation remain largely unknown. Here, we identified CgCaN that encodes a Ca2+-dependent DNase in the fruit of Citrus grandis ‘Tomentosa’, the function of which was studied using calcium ion localization, DNase activity assays, in situ hybridization, and protein immunolocalization. The results suggested that the full-length cDNA of CgCaN contains an ORF of 1011 bp that encodes a protein 336 amino acids in length with a SNase-like functional domain. CgCaN digests dsDNA at neutral pH in a Ca2+-dependent manner. In situ hybridization signals of CgCaN were particularly distributed in the secretory cavity cells. Ca2+ and Ca2+-dependent DNases were mainly observed in the condensed chromatin and in the nucleolus. In addition, spatio-temporal expression patterns of CgCaN and its protein coincided with the time-points that corresponded to chromatin degradation and nuclear rupture during the PCD in the development of the fruit secretory cavity. Taken together, our results suggest that Ca2+-dependent DNases play direct roles in nuclear DNA degradation during the PCD of secretory cavity cells during Citrus fruit development. Given the consistency of the expression patterns of genes regulated by calmodulin (CaM) and calcium-dependent protein kinases (CDPK) and the dynamics of calcium accumulation, we speculate that CaM and CDPK proteins might be involved in Ca2+ transport from the extracellular walls through the cytoplasm and into the nucleus to activate CgCaN for DNA degradation.

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