Drosophila Chromophore Assisted-Laser Inactivation(CALI)

Long-term protein inactivation due to gene knockout or RNA interference (RNAi) can lead to compensatory changes at the molecular level that are difficult to detect or control. Optogenetic techniques avoid these problems in principle due to the precision and reversibility of their manipulation. Chromophore-assisted laser inactivation (CALI) is an optogenetic technique applied in Drosophila that inactivates proteins transiently and precisely to subcellular structural resolution. It is widely used in protein localization and functional studies.

CD BioSciences is committed to technological innovation as an advanced Drosophila genetic technology company. We offer a wide range of chromophores, and support the construction of antibody-bound or target proteins-fused chromophores, adapting to the needs of different customers. We have built a robust in vivo light manipulation platform and optogenetic Drosophila evaluation system to minimize the time and effort of our customers' research.

Local protein inactivation by CALI in a living Drosophila embryo

Fig.1 Local protein inactivation by CALI in a living Drosophila embryo (Hoffman – Kim et al 2007, Monier et al 2010)

Our Service

CALI is a photogenetic inhibition technique that triggers acute inactivation of proteins by light-induced reactive oxygen species (ROS), which has a high spatial and temporal resolution. CD BioSciences achieves real-time inactivation of proteins or pathways by fusing target proteins with photosensitizers, and precise laser excitation optics. We have professional real-time stereoscopic imaging equipment and recommend our clients to use CALI to study protein localization and function in vivo.

In general, we provide fusion protein mutants directly with much lower off-target effects. For proteins that are difficult to label, we recommend specific antibody-bound chromophores that can be used for a broader range of protein targets.

Photosensitizer Choices Advantages Limitations
Enhanced GFP (EGFP) Genetic photosensitizer for whole gene range in Drosophila Weak inactivation
KillerRed Strong inactivation Dimeric state, not suitable for subcellular localization
SuperNova Monomeric variant of KillerRed Monomeric
miniSog Strong and genetic Blue light phototoxicity
FlAsH / ReAsH
  • Labeled synaptic binding protein
  • High ROS efficiency
  • Not genetic
  • Affected by the abundance of targeted proteins
  • May producing toxicity in some cells

Add-On Services

  • Immunostaining
  • Western blot
  • Time-lapse imaging
  • Laser parameters optimization
  • System assessment
  • CALI data collection and processing

Service Features

  • Short action time (< 1s) of reactive oxygen species, which does not cause great damage to cells and tissues
  • Controlled inactivation range, usually 5-6 nm, enabling to study the influence of subcellular structures on cellular processes
  • Digitalization of condition parameters, precise control of light intensity and reaction cycle
  • Precise selection of inactivated proteins
  • Separation of the involvement of various proteins under the time sequence

General Workflow

Workflow of Drosophila Chromophore-Assisted Laser Inactivation (CALI) - CD BioSciences

Why CD BioSciences?

  • Optogenetics technology for time accuracy down to the millisecond level
  • Dedicated technical team enables precise control of single cells and even sub-cellular scales
  • Flexible Drosophila optogenetics customization services, close to the customer's cutting-edge research
  • Documented protocols and raw data for high quality results reports

CD BioSciences has been pioneering bioscience research in the field of Drosophila. CALI is an optogenetics technology in Drosophila research, and our professional scientists focus on cutting-edge technologies to provide satisfactory overall optogenetics services to help our clients achieve more precise and detailed research objectives in neuroscience and cell biology. There are no limitations of our service. If you need any further information or have any question, please feel free to contact us.


  • Hoffman - Kim D, et al. (2007). Chromophore - assisted laser inactivation. Methods in cell biology, 82, 335-354.
  • Monier B, et al, (2010) An actomyosin-based barrier inhibits cell mixing at compartmental boundaries in Drosophila embryos. Nat Cell Biol. 12:60-65, sup pp 61-69.
  • Lin JY, et al. (2013). Optogenetic inhibition of synaptic release with chromophore-assisted light inactivation (CALI). Neuron. 79(2), 241-253.

For research use only. Not intended for any clinical use.

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