Universität zu Köln

Subramanian, Venkatesh Krishna (2016). Characterization of an olfactory receptor mediating aversive behaviour to a death-associated odour. PhD thesis, Universität zu Köln.

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Abstract

Olfaction or the sense of smell is a strong driver of behavior in many animals and is important for their survival. Odors are perceived through a complex molecular recognition process which involves detection of odorants by odorant receptors in olfactory sensory neurons located in the nasal olfactory epithelium. The odorant receptors belong to the G protein–coupled receptors (GPCRs) class of proteins, which includes the trace amine–associated receptors (TAARs), a class of GPCRs associated with the detection of social cues. The present study focused on molecular characterization of a TAAR receptor, TAAR13c, in zebrafish. Cadaverine, a diamine produced by bacterial decarboxylation of lysine, and thus associated with odor emanating from decaying flesh was reported to be the primary ligand for TAAR13c. Aversion to cadaverine was observed in adult Zebrafish by behavior experiments. Here, the cell type expressing TAAR13c receptors was identified as ciliated OSNs. Double-labeling of TAAR13c-expressing neurons with cFos as neuronal activity marker after stimulation with cadaverine showed widespread expression of cFos in many cells, a few of which were also TAAR13c-positive. Another activity marker tested, Egr1, was also found to be nonselective. However, pERK, an activity marker, which does not rely on gene expression, but on phosphorylation and is therefore much faster, showed sparse cells activated after stimulation with cadaverine and a series of other diamines with different chain length. Double-labeling with pERK antibody and TAAR13c antibody showed cellular co-localization of pERK and TAAR13c signals upon cadaverine stimulus. Ontogenetic onset of avoidance behavior was studied using a two channel choice apparatus in Zebrafish larvae. A trend towards avoidance of cadaverine was observed from the larval behavior experiments. 6 Knockout of TAAR13c was attempted using TALEN and Crispr-Cas9 mediated mutagenesis. Unfortunately it was not possible to design completely specific screening strategies due to high sequence identity within the five members of the TAAR13 subfamily and the AT-rich coding region of TAAR13c. Two putative knockout mutations were obtained with optimized screening methods. Finally, the design of new constructs for a TAAR13 subfamily knockout may provide a useful tool in the future for creating a functional Taar13 knockout in zebrafish.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Subramanian, Venkatesh Krishna venkatesh.krishna@ymail.com UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-75356
Journal or Publication Title:	High-affinity olfactory receptor for the death-associated odor cadaverine
Volume:	110
Number:	48
Date:	7 March 2016
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Institute for Genetics
Subjects:	Life sciences
Uncontrolled Keywords:	Keywords Language TAAR13C, Olfaction, Cadaverine UNSPECIFIED
Date of oral exam:	15 April 2016
Referee:	Name Academic Title Korsching, Sigrun Prof. Dr. Schmidt, Joachim PD Dr.
Related URLs:	http://www.pnas.org/content/110/48/19579... http://www.nature.com/articles/srep40892...
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/7535