dc.contributor.advisor | Bucher, Gregor Prof. Dr. | |
dc.contributor.author | Kaufholz, Felix | |
dc.date.accessioned | 2020-10-01T14:52:55Z | |
dc.date.available | 2020-10-01T14:52:55Z | |
dc.date.issued | 2020-10-01 | |
dc.identifier.uri | http://hdl.handle.net/21.11130/00-1735-0000-0005-14A1-E | |
dc.identifier.uri | http://dx.doi.org/10.53846/goediss-8229 | |
dc.identifier.uri | http://dx.doi.org/10.53846/goediss-8229 | |
dc.language.iso | eng | de |
dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
dc.subject.ddc | 570 | de |
dc.title | Investigating the Re-initiation of Segmentation with Temporally Restricted RNAi in Tribolium castaneum | de |
dc.type | doctoralThesis | de |
dc.contributor.referee | Großhans, Jörg Prof. Dr. | |
dc.date.examination | 2020-07-06 | |
dc.description.abstracteng | Much of the success of arthropods is attributed to their body’s segmentation.
Segmentation provides various opportunities for nature to evolve new structures without
greatly impacting overall fitness of the animal. Most knowledge about the development of
segmentation comes from the vinegar fly, Drosophila melanogaster. Drosophila has a
derived long-germ embryogenesis with simultaneous segmentation. Short-germ
embryogenesis or sequential segmentation as in the red flour beetle, Tribolium castaneum,
however, is regarded as a more ancestral state of segmentation. Much less is known about
the genetic processes underlying this sequential segmentation. Recently, a segmentation
clock was identified in Tribolium. This clock utilizes oscillatory expression of the primary
pair-rule genes (pPRGs) to pattern the body axis during both the static blastoderm and the
elongating germband. The segmentation clock receives input from the upstream “posterior
signaling center” and Tc-caudal (Tc-cad). Downstream of the segmentation clock, the
secondary PRGs and the segment polarity genes interpret the pPRG input and provide
further positional information along the AP axis. Studies in Tribolium revealed great insights
into the molecular mechanism of sequential segmentation. However, most of these
findings are based on RNAi leading to the permanent knockdown of gene function. Thus,
they are not suited for studying gene interactions at later stages of the dynamic process of
segmentation and the segmentation clock. I utilized a Viral Suppressors of RNAi (VSR) as a
novel tool to temporally restrict RNAi in Tribolium. This novel tool, hsVSR (heat shock VSR),
allowed me to investigate the segmentation processes in more depth. Specifically, I aimed
to answer the question whether RNAi-induced breakdown of segmentation is irreversible
or if re-initiation of segmentation is possible. With proof-of-concept experiments, I
confirmed the functionality and specificity of the hsVSR system to investigate
segmentation. I could then show that a rescue of segmentation after RNAi-mediated
breakdown is possible by re-initiating the segmentation clock itself. However, rescue of
segmentation by inhibiting RNAi of upstream factors of the segmentation clock was not
possible. Once the “posterior signaling center” is lost, it cannot re-initiate. Additionally, a
possible negative autoregulation of the pPRG Tc-even-skipped was uncovered. Taken
together, I showed the functionality of the hsVSR system during segmentation. I identified
the level at which RNAi inhibition can rescue segmentation within the segmentation
process and provided molecular evidence for the nature of the rescue. | de |
dc.contributor.coReferee | Eichele, Gregor Prof. Dr. | |
dc.contributor.thirdReferee | Posnien, Nico Dr. | |
dc.contributor.thirdReferee | Jackson, Daniel John Prof. Dr. | |
dc.contributor.thirdReferee | Christoph, Bleidorn Prof. Dr. | |
dc.subject.eng | Developmental Biology | de |
dc.subject.eng | Tribolium | de |
dc.subject.eng | Segmentation | de |
dc.subject.eng | Arthropods | de |
dc.subject.eng | RNAi | de |
dc.subject.eng | EvoDevo | de |
dc.subject.eng | Hybridization Chain Reaction | de |
dc.identifier.urn | urn:nbn:de:gbv:7-21.11130/00-1735-0000-0005-14A1-E-9 | |
dc.affiliation.institute | Biologische Fakultät für Biologie und Psychologie | de |
dc.subject.gokfull | Biologie (PPN619462639) | de |
dc.identifier.ppn | 1734478063 | |