Abstract
With the progress of optogenetics, the activities of genetically identified neurons can be optically silenced to determine whether the neurons in question are necessary for the network performance of the behavioral expression. This logical induction is expected to be improved by the application of the Na+ pump rhodopsins (NaRs), which hyperpolarize the membrane potential with negligible influence on the ionic/pH balance. Here, we made several chimeric NaRs between two NaRs, KR2 and IaNaR from Krokinobacter eikastus and Indibacter alkaliphilus, respectively. We found that one of these chimeras, named I1K6NaR, exhibited some improvements in the membrane targeting and photocurrent properties over native NaRs. The I1K6NaR-expressing cortical neurons were stably silenced by green light irradiation for a certain long duration. With its rapid kinetics and voltage dependency, the photoactivation of I1K6NaR would specifically counteract the generation of action potentials with less hyperpolarization of the neuronal membrane potential than KR2.
MeSH terms
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Amino Acid Sequence
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Animals
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Biological Transport
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Cell Line
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Cytophaga / genetics
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Cytophaga / metabolism
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Electrophysiological Phenomena
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Gene Expression
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Ions / metabolism
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Light
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Membrane Potentials / radiation effects
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Neurons / metabolism
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Neurons / radiation effects
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Optogenetics*
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Rats
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Rhodopsin / chemistry
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Rhodopsin / genetics*
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Rhodopsin / metabolism*
Grants and funding
This study was supported by a Grant-in-Aid for Scientific Research (No. 25250001 to HY and No. 25290002 to TI) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan:
http://www.jsps.go.jp/english/e-grants/grants01.html, a Grant-in-Aid for Scientific Research on Innovative Areas “Adaptive Circuit Shift” (No. 15H01413 to HY) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan:
http://www.jsps.go.jp/english/e-grants/grants01.html, a Grant-in-Aid for challenging Exploratory Research (No. 15K15025 to HY), MEXT, Japan:
http://www.jsps.go.jp/english/egrants/grants01.html and JST, Strategic International Collaborative Research Program, SICORP.