Journal Article

Extraoral expression and characterization of bitter taste receptors in Astyanax mexicanus (Mexican tetra fish)

Bhatia, V., de Jesus, V.C., Shaik, F.A., Jaggupilli, A., Singh, N., Chelikani, P. and Atukorallaya, D.

Record Number:
5988
Year:
2022
Journal:
FASEB BioAdvances
Pages:
574-584
Volume:
4
Notes:
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is cited, the use is non-commercial and no modifications
PMCID:
http://doi.org/10.1096/fba.2022-00032
URL:
www.fasebbioadvances.org
Abstract:
The chemical senses of olfaction and taste are well developed in fish and play a vital role in its various activities such as navigation, mate recognition, and food detection. The small teleost fish Astyanax mexicanus consists of interfertile river-dwelling and cave-dwelling populations, referred to as “surface fish” and “cavefish” respectively. An important anatomical feature of cavefish is the lack of eyes leading them to be referred to as blind fish and suggesting an enhanced functional role for other senses such as taste. In this study, we characterize the expression of bitter taste receptors (T2Rs or Tas2Rs) in A. mexicanus and investigate their functionality in a heterologous expression system. The genome database of A. mexicanus (ensemble and NCBI) showed 7 Tas2Rs, among these Tas2R1, Tas2R3, Tas2R4, and Tas2R114 are well characterized in humans and mice but not in A. mexicanus. Therefore, the 4 Tas2Rs were selected for further analysis and their expression in A. mexicanus was confirmed by in situ hybridization and RT-PCR in early developmental stages. These Tas2Rs are expressed in various oral and extraoral organs (liver, fins, jaws, and gills) in A. mexicanus, and Tas2R1 has maximum expression and is localized throughout the fish body. Using the heterologous expression of A. mexicanus T2Rs in HEK293T cells coupled with cell-based calcium mobilization assays, we show that A. mexicanus T2Rs are activated by commonly used fish food and known bitter agonists, including quinine. This study provides novel insights into the extraoral expression of T2Rs in A. mexicanus and suggests their importance in extraoral food detection. KEYWORDS Astyanax mexicanus, bitter taste receptors, calcium mobilization, in situ hybridization, taste buds, teleost
Times Cited:
1
Relevent Species:
Astyanax jordani (Hubbs and Innes 1936) Buckup 2003