What are the common reporter genes?

Reporter genes are genes that produce an enzyme or protein receptor when they are introduced into target cells such as circulating white cells or brain tissues. The enzyme or protein receptor binds, traps or transports a subsequently injected imaging probe. The most commonly used reporter genes include: 

• Green fluorescent protein (GFP) – GFP, a naturally occurring protein derived from the jellyfish Aequorea Victoria, is widely used to quantify gene expression. It causes cells that express it to glow bright green under UV light and is particularly useful in fluorescence microscopy techniques.
• Luciferase – Luciferase, a naturally occurring enzyme derived from the firefly Photinus pyralis, catalyzes reactions with its substrate to produce blue or yellow-green light, depending on the luciferase gene. The advantage of using this reporter gene is that it produces virtually background-free fluorescence. This is because luciferase bioluminescence does not require light excitation, which minimizes autofluorescence. 
• GUS assay - GUS assay (using β-glucuronidase) stains cells blue and is widely used to detect a single cell in plant science. The advantage of GUS assay is that it doesn’t require complicated equipment. However the downside is that cells are killed in the process.  
• GST (glutathione S-transferase) Antibody - GST is a widely used protein fusion tag. It is inducible and gives high-level intracellular expression of genes or gene fragments, making it the preferred choice for mammalian protein expression studies.