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We offer a diverse array of cell-permeant fluorescent stains that selectively associate with the mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and nucleus in live cells (Figure 12.1.1). These probes, which include our MitoTracker, LysoTracker, LysoSensor, RedoxSensor and ER-Tracker organelle stains (Molecular Probes fluorescent organelle stains—Table 12.1), are compatible with most fluorescence instrumentation and provide researchers with powerful tools for investigating respiration, mitosis, apoptosis, multidrug resistance, substrate degradation and detoxification, intracellular transport and sorting and more. Importantly, unlike antibodies, these fluorescent probes can be used to investigate organelle structure and activity in live cells with minimal disruption of cellular function (photo). The red-fluorescent organelle stains are particularly useful for demonstrating colocalization with Green Fluorescent Protein (GFP) expression ( Using Organic Fluorescent Probes in Combination with GFP—Note 12.1).

In addition to these organelle-selective organic dyes, we offer CellLight targeted fluorescent protein–based markers, comprising BacMam expression vectors encoding an autofluorescent protein fused to a site-selective targeting sequence. These reagents are available for labeling a variety of organelles—including mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and nucleus, as well as several subcellular structures such as actin filaments and microtubules—in live mammalian cells ( CellLight reagents and their targeting sequences—Table 11.1). In this chapter, we discuss the CellLight reagents targeted specifically to organelles. CellLight reagents incorporate all the customary advantages of BacMam delivery technology, including high transduction efficiency and long-lasting and titratable expression ( BacMam Gene Delivery and Expression Technology—Note 11.1).

Fluorescent cytoskeleton probes, including CellLight targeted fluorescent proteins, are discussed in Probes for Cytoskeletal Proteins—Chapter 11. Fluorescent plasma membrane stains, as well as CellLight membrane-targeted fluorescent proteins, are discussed in Tracers for Membrane Labeling—Section 14.4. A variety of probes for phagovacuoles, endosomes and lysosomes—such as membrane markers, ligands for studying receptor-mediated endocytosis and CellLight endosome-targeted fluorescent proteins—are discussed in Probes for Following Receptor Binding and Phagocytosis—Section 16.1.

Design your own multicolor experiments using our online Cell Staining Tool. More information is available at

Figure 12.1.1 Diagram of an animal cell.