Creative Biolabs

New Fast Genetically Encoded Calcium Indicators: jGCaMP8

New Fast Genetically Encoded Calcium Indicators: jGCaMP8

The key to brain science research is to realize the real-time observation of the activity of neuron clusters, and to analyze the function and structure of neural circuits on the whole brain scale through the structure tracking of specific neural circuits and their activity manipulation.

Calcium imaging is one of the most important technologies in the field of life sciences today. Since changes in the concentration of calcium ions in cells can reflect the activity of cells, we can characterize cell activities by observing their changes. Nowadays, calcium imaging has been used in various disciplines from neuroscience to plant physiology research.

The principle of calcium ion imaging technology lies in the properties of calcium ion-sensitive proteins (genetically encoded calcium indicators, GECIs). Taking the GCaMP protein as an example, the binding of calcium and the GCaMP protein can stimulate the emission of green fluorescence, so that the experimenter can collect and record the instantaneous fluorescence changes by means of two-photon fluorescence microscope or optical fiber recording.

3-1-3-New-Fast-Genetically-Encoded-Calcium-Indicators-jGCaMP8-1 Figure 1 The basic structure and principle of GCaMP protein (Sun, 2013)

Neuroscience is the most widely used subject of calcium imaging technology. Based on GECIs expressed by genetic methods, scientists can observe the cell activities of the nervous system non-invasively. The application of calcium ion imaging

technology in neuroscience includes: observing and recording the activities of population cells (mainly tracking the fluorescent signals of cell bodies), and recording the activities of cell substructural units (such as axons, dendrites, or local synapses). With the increasing demand for research, people continue to improve calcium-sensitive proteins. At present, the more mature ones are the GCaMP6 and jGCaMP7 series. With the help of these tools, we can detect changes in calcium ions caused by a single action potential, and the observation time can be accurate to the millisecond level, up to several months of continuous observation.

GCaMP6 Series

The sixth-generation GCaMP protein (GCaMP6) includes three different subtypes: GCaMP6s, GCaMP6m, and GCaMP6f, which have different characteristics and need to be selected according to experimental requirements [1].

Calcium Indicators Features Applications
GCaMP6s Ultrasensitive GCaMP variant; slow kinetics Suitable for low-frequency signals
GCaMP6m Ultrasensitive GCaMP variant; medium kinetics Suitable for high-frequency signals
GCaMP6f Ultrasensitive GCaMP variant; fast kinetics Wide range applications

jGCaMP7 Series

jGCaMP7 (Janelia GCaMP7, different from G-CaMP7), including four types of proteins with different characteristics: jGCaMP7s, jGCaMP7f, jGCaMP7b, jGCaMP7c[2]. The jGCaMP7 sensors were tested in vitro and in vivo, and show substantially better performance than the GCaMP6 sensors.

Calcium Indicators Features Applications
jGCaMP7s Sensitive and slow The sensitivity is more than five times that of GCaMP6s, which is suitable for detection of single action potentials.
jGCaMP7f Fast kinetics The sensitivity is more than five times that of GCaMP6f, which is suitable for detection of single action potentials.
jGCaMP7s Sensitive and slow The sensitivity is more than five times that of GCaMP6s, which is suitable for detection of single action potentials.
jGCaMP7f Fast kinetics The sensitivity is more than five times that of GCaMP6f, which is suitable for detection of single action potentials.

jGCaMP8 Series

Although GCaMP6 and jGCaMP7 have been widely verified and applied, there are still many shortcomings that need to be improved. Recently, we have been fortunate to see great progress in this field.

The Loren L. Looger laboratory of HHMI Janelia and the GENIE Project team have developed a new generation of GCaMP protein - jGCaMP8. The new jGCaMP8 sensor has a faster dynamic curve and a high degree of sensitivity [3]. Specifically, the sensors are:

  • jGCaMP8f (fast): 4x faster rise time, 2.5x faster decay time than jGCaMP7f.
  • jGCaMP8m (medium): almost 4x faster rise time and 3.5x more sensitive than jGCaMP7f.
  • jGCaMP8s (sensitive): 2x more sensitive than jGCaMP7s, >2x faster than jGCaMP7f (at 1AP).

3-1-3-New-Fast-Genetically-Encoded-Calcium-Indicators-jGCaMP8-2 Figure 2 Reaction characteristics of jGCaMP8 protein [3]

As a pioneer in advanced technical services in the field of neuroscience, Creative Biolabs has developed this type of viral vector based on the jGCaMP8 component information selflessly disclosed by HHMI Janelia scientists. Both direct expression and Cre-dependent expression vectors are available.

Direct Expression Cre-dependent Expression
pAAV-syn-jGCaMP8f-WPRE pAAV-syn-FLEX-jGCaMP8f-WPRE
pAAV-syn-jGCaMP8m-WPRE pAAV-syn-FLEX-jGCaMP8m-WPRE
pAAV-syn-jGCaMP8s-WPRE pAAV-syn-FLEX-jGCaMP8s-WPRE

As one of the key technologies of neuroscience research, calcium ion imaging has contributed greatly to our understanding of the nervous system. With the birth of a new generation of jGCaMP8, scientists can monitor the physiological activities of cells more clearly.

Appendix

Calcium Imaging Virus Vector List at Creative Biolabs

Cat
NTA-2012AD-P475
NTA-2012AD-P476
NTA-2012AD-P477
NTA-2012AD-P478
NTA-2012AD-P483
NTA-2012AD-P484
NTA-2012AD-P485
NTA-2012AD-P487
NTA-2012AD-P488
NTA-2012AD-P489
NTA-2012AD-P490
NTA-2012AD-P491
NTA-2012AD-P492
NTA-2012AD-P493
NTA-2012AD-P494
NTA-2012AD-P495
NTA-2012AD-P496
NTA-2012AD-P497
NTA-2012AD-P498
NTA-2012AD-P499
NTA-2012AD-P500
NTA-2012AD-P501
NTA-2012AD-P502
NTA-2012AD-P503
NTA-2012AD-P504
NTA-2012AD-P505
NTA-2012AD-P506
NTA-2012AD-P507
NTA-2012AD-P508
NTA-2012AD-P509
NTA-2012-ZP510
Receptor
jGCaMP7s
jGCaMP7s
jGCaMP7f
jGCaMP7f
GCaMP6s
GCaMP6s
GCaMP6s
GCaMP6s
GCaMP6s
GCaMP6s
GCaMP6m
GCaMP6f
GCaMP6f
GCaMP6f
GCaMP6f
GCaMP6f
GCaMP6f
GCaMP6f
jRGECO1a
jRGECO1a
jRGECO1a
jRCaMP1b
CaMPARI2
CaMPARI
GCaMP6m-XC
XCaMP-Y
XCaMP-Y
XCaMP-R
XCaMP-R
XCaMP-B
XCaMP-B
Promoter
hSyn
hSyn
hSyn
hSyn
CMV
EF1a
EF1a
CaMKIIa
sGFAP
TRE
EF1a
CMV
CMV
EF1a
EF1a
CAG
hSyn
CaMKIIa
hSyn
hSyn
GfaABC1D
hSyn
hSyn
hSyn
hSyn
hSyn
hSyn
hSyn
hSyn
hSyn
hSyn
Expression
Direct Expression
Cre-on
Direct Expression
Cre-on
Direct Expression
Cre-on
Cre-on
Direct Expression
Direct Expression
Direct Expression
Cre-on
Direct Expression
Direct Expression
Cre-on
Cre-on
Direct Expression
Direct Expression
Direct Expression
Cre-on
Direct Expression
Direct Expression
Direct Expression
Cre-on
Cre-on
Direct Expression
Direct Expression
Cre-on
Direct Expression
Cre-on
Direct Expression
Cre-on

References

  1. Tsai-Wen Chen. et al., Ultra-sensitive fluorescent proteins for imaging neuronal activity. Nature. 2013 Jul 18;499(7458):295-300. doi: 10.1038/nature12354.
  2. Hod Dana, et al., High-performance GFP-based calcium indicators for imaging activity in neuronal populations and microcompartments bioRXiv, 2018, DOI: 10.1101/434589
  3. Zhang et al Janelia Research Campus. Online resource. 2020
  4. Sverre Grødem., et al. An updated suite of viral vectors for in vivo calcium imaging using local and retro-orbital injections. doi: https://doi.org/10.1101/2021.05.14.443815
  5. Sun, Xiaonan R., et al. "Fast GCaMPs for improved tracking of neuronal activity." Nature communications 4.1 (2013): 1-10.

For Research Use Only. Not For Clinical Use.
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