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Updated: Jul 12, 2026
07:09
A Bioinformatics Pipeline for Investigating Molecular Evolution and Gene Expression using RNA-seq
Published on: May 28, 2021
Evolutionary gene number variation and functional diversification of retinal EAATs are reflected in expression
André Lehnherr1, Peter Kovermann2, Christoph Fahlke2
1Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
Scientific Reports
|July 10, 2026
Summary
Retinal excitatory amino acid transporter (EAAT) expression and function have evolved significantly across vertebrate species. This study reveals diverse EAAT roles in mammals versus zebrafish, cautioning against direct extrapolation of mouse retinal glutamate handling.
Area of Science:
- Neuroscience
- Evolutionary Biology
- Molecular Biology
Background:
- Excitatory amino acid transporters (EAATs) are crucial for retinal glutamate signaling and neuroprotection.
- Vertebrate evolution, including genome duplications and gene losses, raises questions about conserved EAAT functions in the retina.
Purpose of the Study:
- To investigate the evolutionary diversification of EAAT expression and function across different vertebrate clades.
- To compare EAAT patterns in mammalian and teleost retinas.
Main Methods:
- Retinal expression mapping.
- Transgenic reporter assays in zebrafish.
- Electrophysiological characterization of EAAT proteins.
Main Results:
- Mammalian retinas show distinct EAAT1-5 expression shifts compared to non-therian vertebrates due to gene loss.
- Zebrafish retinas predominantly express EAAT2a in Muller glia and EAAT2b/EAAT7 in neurons, differing from mouse EAAT1 (glial) and EAAT2 (neuronal) expression.
- Mouse EAAT1 regulatory elements drive neuronal expression in zebrafish, indicating divergent regulatory logic.
- Functional differences in EAATs correlate with expression patterns: glial EAATs primarily clear glutamate, while neuronal EAATs modulate excitability.
Conclusions:
- Retinal EAAT expression and function have been significantly reshaped during vertebrate evolution.
- Caution is advised when extrapolating mouse retinal glutamate handling mechanisms to non-mammalian species.
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