Maintaining cells in an undifferentiated totipotent state is essential for initiating
developmental programs that lead to a fully formed organism in each generation and for
maintaining immortal germ cells across generations. Caenorhabditis elegans is a powerful
genetic model organism to study early germ cell development due to the animal’s
transparency and the ability to screen for mutant phenotypes. However, our ability to use
standard techniques to study gene expression using fluorescent reporter genes has been
limited due to germline-specific silencing mechanisms that repress transgenes. Therefore, we
lack even basic knowledge of how expression is regulated in C. elegans germ cells. In this
study, we develop methods to overcome these silencing mechanisms by using a class of noncoding
DNA, called Periodic An/Tn Clusters (PATCs), to prevent transgene silencing in the
germline. We use these improved tools to test the proposed role of putative germline-specific
regulatory DNA motifs and the role a periodic TT signal within germline promoters. We
fused GFP to the promoter of a germline expressed gene (pcn-1), which is enriched for
PATCs and contains a germline-specific motif (TTAAAG). Our results show that despite
enrichment and phylogenetic conservation, the TTAAAG motif is not required for germline
expression. To test additional motifs and periodic TTs, we have designed a system that will
allow us to test synthetic gene fragments for bi-directional germline expression. These tools
will allow us to rapidly test motif redundancy, motif spacing, and TT periodicity using gfp
and rfp signals in the germline and will enable experiments aimed at understanding the role
of germline regulatory elements.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/664481 |
| Date | 07 1900 |
| Creators | Alkoblan, Samar |
| Contributors | Jensen, Christian Froekjaer, Biological and Environmental Sciences and Engineering (BESE) Division, Blilou, Ikram, Mahfouz, Magdy M. |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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