Universität zu Köln

Conrads, Kai Hans (2024). New insights into the gene regulatory network that regulates dorsoventral axis patterning in Oncopeltus fasciatus. PhD thesis, Universität zu Köln.

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Abstract

Toll-dependent dorsoventral axis patterning in Drosophila represents one of the best understood gene regulatory networks. However, outside the insects Toll is not known for a patterning function, but rather for a role in pathogen defense. In most other animals the dorsoventral axis is patterned by BMP signaling. How the shift from a BMP-based to a Toll-dominated mode of dorsoventral axis patterning within the insect lineage evolved has remained elusive. Previous work has shown that in the milkweed bug Oncopeltus fasciatus Toll is only required to polarize a dynamic BMP signaling network, an architecture that resembles characteristics of dorsoventral axis patterning in vertebrates and other animals more than any other insect studied so far. In this work, I established an embryonic microinjection protocol to inject Toll and BMP pathway components to ectopically activate these pathways in wild-type and dorsalized Toll knockdown embryos and analyzed the induced gene expression patterns via in situ hybridizations. Together with phenotypic analysis my experiments revealed, that the transcription factor Snail is a crucial component of the BMP/Sog system of Oncopeltus and thus has an axis patterning function that is not described for any other organism. I propose a gene regulatory network including Snail that extends the previous BMP/Sog system of Oncopeltus and is able to pattern the mesoderm, ectoderm and mesectoderm. In addition, I generated transcriptomes of both wild type and RNAi-mediated knockdown embryos, targeting essential dorsoventral patterning genes of the Toll and BMP pathway. I performed RNAseq and analysed a subset of differentially expressed genes via in situ hybridizations and RNAi-mediated knockdown generation. Several expression patterns were found that have never been described before, including two markers of the serosa, an embryonic fate that lacked a distinct marker in Oncopeltus as of yet.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Conrads, Kai Hans kai.conrads@gmx.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-726275
Date:	2024
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Zoologisches Institut
Subjects:	Life sciences
Uncontrolled Keywords:	Keywords Language Oncopeltus fasciatus UNSPECIFIED Dorsoventral Patterning UNSPECIFIED Gene Regulatory Networks UNSPECIFIED Snail UNSPECIFIED
Date of oral exam:	26 February 2024
Referee:	Name Academic Title Roth, Siegfried Prof. Dr. Hammerschmidt, Matthias Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/72627