Early growth response 1 (Egr1) is a transcription factor critical for learning and memory in the hippocampus and pituitary cell differentiation. Egr1 has been shown to extend continuation of the long-term potentiation in the hippocampus and is credited for forming long-term memories. The somatotrophs in the pituitary produce growth hormone and are found to be decreased in Egr1KO mice. These animals are also found to be sterile due to a decrease in LHB, which blocks ovulation. All previous studies have evaluated these physiological processes with complete Egr1KO research strains or antisense oligonucleotides, up until now, no data specific to individual type of cells has been generated. In an attempt to focus on the understanding of the functions of Egr1 gene in neural cell lineage, we are using an Egr1cKO Nestin-Cre model. Nestin allows for targeting neuronal lineage specific cells.
In Chapter 1, we provide a systemic view of Egr1 gene and Nestin-Cre as a system for generating conditional knockout mouse strains. The Chapter begins with the identification of Egr1 gene and its protein structure, then proceeds to grasp its link to memory with behavior testing. The critical role of Egr1 in the pituitary and what cell populations are affected is also described. The same goes for Nestin-Cre, along with its limitations and understanding how to account for them in a study. The Egr1cKO Nestin-Cre system is the best form to understand neurological cell populations with Egr1 removal.
In Chapter 2 and Chapter 3, we employ the Egr1cKO Nestin-Cre mouse model to understand cell-specific knockout of Egr1 in the nervous system by evaluating the hippocampus and pituitary. We explore learning and memory through behavioral tests and ribonucleic acid sequencing (RNA-seq) analysis to understand gene expression changes with Egr1 removal. Females showed higher activity during behavior tests, with more movement in the elevated plus maze and lower freezing times during the contextual fear conditioning. RNA-seq had higher changes in females than males but was not affected by the Nestin-Cre system overall. The same RNA-seq changes in the pituitary gland were present, with females having higher genomic differentiation. Females had growth-specific pathways altered by Nestin-Cre. / Doctor of Philosophy / Genetics has become a very important forerunner in scientific research. One gene that has become important in many different research arenas is Early growth response 1 (Egr1). This particular gene is critical for learning, memory, and cell changes in the pituitary. In Chapter 1, we have analyzed the current research landscape of information on Egr1 in its functions with learning and memory, as well as the pituitary. Most previous studies that have been completed only evaluate this gene by its removal from the entire body. This leaves a large gap in information about how this gene functions with specific cell types. To limit the type of cells from which Egr1 has been removed, we have selected Nestin-Cre, a tool to remove genes from neuronal stem cells. The capabilities and limitations of this tool have also been explained in this chapter, along with how the two together can accomplish a cell-specific knockout of Egr1.
In Chapter 2, we have constructed an experiment with behavioral tests for mice, along with RNAseq data from the hippocampus to evaluate what changes have occurred in the Egr1cKO Nestin-Cre model. Female mice are more active in the behavioral test, including the elevated plus maze (EPM) and Contextual fear conditioning (CFC), than male mice. The same holds for differences in the RNAseq data as well.
In Chapter 3, the pituitary of Egr1cKO Nestin-Cre mice is the main focus. We evaluated RNAseq data and determined growth rates of transgenic mice. The mice had different growth rates over twelve weeks between the controls and the knockout. The RNAseq data also revealed many differences between males and females. Female mice had specific growth genes effects by the knockout of Egr1
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/116161 |
| Date | 29 August 2023 |
| Creators | Swilley, Cody Lynn |
| Contributors | Biomedical and Veterinary Sciences, Xie, Hehuang David, Kehn-Hall, Kylene Wesley, Hodes, Georgia E., Jarome, Timothy J., Zimmerman, Kurt L. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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