Histological Assessment of Cre-loxP Genetic Recombination in the Aging Subventricular Zone of Nestin-CreERT2/Rosa26YFP Mice

Author(s):  
Saad Omais ◽  
Nour N. Halaby ◽  
Karl John Habashy ◽  
Carine Jaafar ◽  
Anthony T. Bejjani ◽  
...  
Author(s):  
E. H. Egelman ◽  
X. Yu

The RecA protein of E. coli has been shown to mediate genetic recombination, regulate its own synthesis, control the expression of other genes, act as a specific protease, form a helical polymer and have an ATPase activity, among other observed properties. The unusual filament formed by the RecA protein on DNA has not previously been shown to exist outside of bacteria. Within this filament, the 36 Å pitch of B-form DNA is extended to about 95 Å, the pitch of the RecA helix. We have now establishedthat similar nucleo-protein complexes are formed by bacteriophage and yeast proteins, and availableevidence suggests that this structure is universal across all of biology, including humans. Thus, understanding the function of the RecA protein will reveal basic mechanisms, in existence inall organisms, that are at the foundation of general genetic recombination and repair.Recombination at this moment is assuming an importance far greater than just pure biology. The association between chromosomal rearrangements and neoplasms has become stronger and stronger, and these rearrangements are most likely products of the recombinatory apparatus of the normal cell. Further, damage to DNA appears to be a major cause of cancer.


2019 ◽  
Vol 8 ◽  
pp. 1511
Author(s):  
Marzieh Shahpari ◽  
Hadi Aligholi ◽  
Mohammad Reza Namavar ◽  
Farzaneh Vafaee ◽  
Masoumeh Emamghoreishi

Background: There is no universally accepted behavioral scoring to define the early development of phenothiazine (PTZ) kindling. Therefore, studies investigating alterations of neurogenesis in the PTZ model were mainly focused on full kindled animals rather than early stages of kindling. This study aimed to determine an appropriate behavioral index for categorizing stages of PTZ kindling progress and to evaluate neurogenesis during PTZ kindling. Materials and Methods: Twenty-four mice were intraperitoneally injected with a sub convulsive dose of PTZ (40mg/kg) every other day until they became full kindled. The first occurrence of different seizure behaviors and their durations were recorded during kindling development, and the different stages of kindling were categorized. Neurogenesis was evaluated in the lateral subventricular zone (SVZ) at each stage of kindling by immunofluorescence staining. Results: First occurrence of restlessness, motionless staring, hind limb tonic extension, Straub’s tail, myoclonic jerk, and tonic-clonic were sequentially observed in more than 80% of animals with increasing PTZ injections. The duration of the myoclonic jerk was significantly longer than the other seizure behaviors. The significantly higher percentage of BrdU-positive cells was found in SVZ of mice showing tonic-clonic in comparison to other seizure behaviors. Conclusion: A hierarchy behavior was observed during the kindling process when considering the first occurrence of seizure behaviors. We defined the first occurrence of restlessness, motionless, hind limb tonic extension and Straub’s tail behaviors as an early phase, myoclonic jerk as a borderline phase and tonic-clonic as a late phase of PTZ-induced kindling. Our results indicated an enhanced SVZ neurogenesis at the late phase of kindling. [GMJ.2019;8:e1511]


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