Dissertation
Investigating DNA Methylation Dynamics with Transgenic LINE-1 Mouse Models
Doctor of Philosophy (PhD), Washington State University
01/2013
Handle:
https://hdl.handle.net/2376/4946
Abstract
The mouse and human genomes are saturated with retrotransposons or repetitive elements. While most repetitive elements cannot mobilize by themselves, a specific class of retrotransposon, Long Interspersed Element Type 1 (LINE-1, L1) encodes the molecular machinery to move itself and other retroelements, classifying it as the only autonomous repetitive element found in both genomes. To explore the inner-workings of L1, research groups have developed L1 transgenes capable of indicating retrotransposition through reporter gene expression or molecular markers. However, many L1 transgenes have low activity, hindering progress to better understand L1 biology. A major advancement toward generating a better L1 transgene was made with the construction of a hyperactive L1 transgene (<italic>ORFeus</italic>) capable of retrotransposing at high levels in mice. In the first study, we further characterized the retrotransposition activity of both a high- and single-copy <italic>ORFeus</italic> transgene in mice and reported the highest retrotransposition activity in somatic tissues hitherto. The second study used the <italic>ORFeus</italic> transgene to incorporate poly(A) repeats into the genome through retrotransposition to study their mutability dynamics. We observed dynamic and rapid shortening of long poly(A) repeats (>100 As) which led to somatic and germ cell mosaicism. In the third study, we used the <italic>ORFeus</italic> transgene to mobilize a CpG-rich sequence to random locations in the mouse genome and characterized the DNA methylation patterns. We observed a striking difference in somatic and germ cell methylation; while insertions in somatic tissues were consistently hypermethylated, insertions in germ cells were hypomethylated. In the fourth study, we examined the flanking genomic regions of the germline insertions for changes in methylation pattern. Here, we observed a two-way cross talk between the methylation state of the insertions and flanking genomic DNA. The work presented here demonstrates how, by using L1 transgenes in an <italic>in vivo</italic> model, we were able to capture the subtle ways L1 mobilization changes the dynamics of the genome and epigenome.
Metrics
4 File views/ downloads
22 Record Views
Details
- Title
- Investigating DNA Methylation Dynamics with Transgenic LINE-1 Mouse Models
- Creators
- James Michael Rosser
- Contributors
- Wenfeng An (Advisor)Chulhee Kang (Committee Member)Kwan Hee Kim (Committee Member)Raymond Reeves (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Molecular Biosciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 265
- Identifiers
- 99900581849401842
- Language
- English
- Resource Type
- Dissertation