Universität zu Köln

Seibert, Jan (2017). Characterizing multiple roles of pannier during embryogenesis, as revealed with an augmented fluorescent live imaging toolkit, in the beetle Tribolium castaneum. PhD thesis, Universität zu Köln.

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Abstract

Embryogenesis in the beetle Tribolium castaneum relies on the morphogenetic movements of the two extraembryonic membranes, amnion and serosa. It is due to their function and concerted development that the embryo is able to survive. During formation of both membranes, their movements include tissue expansion, as well as intra-tissue fusion and inter-tissue separation. In late development, the coordinated withdrawal and subsequent degeneration of both membranes facilitates embryonic dorsal closure, during which the amnion replaces the serosa as a transient yolk cover. To learn more about the amnion, the transcription factor Tc pannier (Tc-pnr). The wild type expression pattern of Tc-pnr was determined and the observed defects after parental RNA interference were analyzed. Tc-pnr deficient embryos display a pronounced hole in the dorsal cuticle and a characteristic bending towards the dorsal side. This specific phenotype is the result of a defect during dorsal closure. In Drosophila melanogaster, the dorsal hole is due to a loss of Dm decapentaplegic (Dm-dpp) expression in the dorsal most cells. It could be shown that in Tribolium, Tc-pnr and Tc-dpp are co-expressed in corresponding cells of the dorsal ectoderm as well. This suggests that Tc-pnr has an essential function in dorsal closure. After loss of Tc-pnr expression in the amnion, where it was shown to be expressed at least until mid embryogenesis, the amnion displays various defects around the process of dorsal closure. Intriguingly, the amnion ruptures ectopically and withdraws independent from the serosa. To investigate the disturbed interplay between the serosa and the amnion, an existing enhancer trap line expressing EGFP in the amnion was modified, by using a combination of CRISPR/Cas9 and homology directed repair, to express DsRed2 instead. The DsRed2 expressing amnion line can now be crossed to another line expressing EGFP in the serosa.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Seibert, Jan j_seibert@gmx.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-74581
Date:	13 March 2017
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Institut für Entwicklungsbiologie
Subjects:	Life sciences
Uncontrolled Keywords:	Keywords Language extraembryonic membrane, serosa, amnion, Tribolium castaneum, Oncopeltus fasciatus, pannier, CRISPR/Cas9 English
Date of oral exam:	18 January 2017
Referee:	Name Academic Title Panfilio, Kristen Dr. Roth, Siegfried Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/7458