Interaktion und Funktion möglicher Signalelemente downstream von Hydra FGFR
Abstract
The fundamental mechanism of signal transduction by fibroblast growth factor receptors (FGFRs) is highly conserved across the animal kingdom and essential for key functions such as migration, proliferation, and differentiation during growth and development processes. FGF receptors have already been found in the early evolutionary lineage of Cnidaria. In the freshwater polyp Hydra vulgaris, six fibroblast growth factors were known up to 2015 (Lange et al. 2014). In 2024, fifteen additional FGFs were identified (Dissertation Ohler 2025; Ohler et al., submitted for review). In addition, two canonical receptors FGFRa (kringelchen) (Hasse et al. 2014; Sudhop et al. 2004) and FGFRb (Rudolf et al. 2013; Suryawanshi et al. 2020) were described, as well as the downstream signaling elements Grb2, Crkl, Shp2, Sos2 (Suryawanshi et al. 2020) and the inhibitor Spry2 identified (Dissertation Suryawanshi 2017).
In the present work, the downstream signaling elements were examined for their function during the bud detachment. Moreover, a new potential FGF receptor in Hydra was identified. Through co-expression analyses using fluorescence in situ hybridization, it could be confirmed that the downstream signaling elements are fully or partially co-expressed with fgfra from the bud stage 8 (start of the detachment phase). To observe an effect on bud detachment, siRNA knockdown was performed during budding at bud stage 3 (see transfection of oligonucleotides and inhibition by SU5402 in Sudhop et al. 2004. There, the non-detaching bud phenotype known from Sudhop et al. 2004 could be reproduced. Depending on the downstream signaling element, the non-detaching bud phenotype was observed with varying significance. Since in Suryawanshi et al. 2020 neither the mRNA expression of the DOF homolog nor of the FRS2 homolog at the bud base could be demonstrated, the question arises whether the adaptor proteins Crkl and Grb2 can directly bind to the FGF receptor in Hydra. In a protein-interaction study using the yeast two-hybrid system, however, no protein interaction between FGFRa and the respective potential docking proteins Crkl and Grb2 could yet be detected.
The new potential FGF receptor FGFRl-x4, after examination of the coding sequence, possesses all characteristic protein domains, phosphorylation sites, and binding motifs of Hydra FGFRa. Through a co-expression analysis with fgfra, it could be confirmed that fgfrl-x4 is cellular co-expressed with fgfra.
The present work thus provides new insights into possible functions of the downstream signaling elements of FGFRa, identifies with the newly discovered FGFR-lx4 a potential new interaction partner, and serves as a basis for further investigations into the interaction of FGFRs and the downstream signaling elements in signal transduction in Hydra.
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Metadata
Contributors
Supervisor:
Dates
Issued: 2025-11-24
Faculty
FB17:Biologie
Language
de
Keywords
Hydra vulgarissiRNAFGFR-Signaling
DFG-subjects
2.11-06 - Entwicklungsbiologie
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Kneifert, Lars: Interaktion und Funktion möglicher Signalelemente downstream von Hydra FGFR. : 2025-11-24.
License
This item has been published with the following license: In Copyright