What is GFP? Green Fluorescent Protein (GFP) is a 26.9 kDa protein first identified in crystal jellyfish, Aequorea victoria. It was discovered that when exposed to blue or ultraviolet light the protein fluoresces green. After GFP was first expressed in E. coli in 1994 it was soon confirmed that GFP can also be successfully expressed in other organisms as well. Since then, not only have many fluorescent proteins of different colors been generated, but their function is enhanced to provide a faster and stronger fluorescent signal. GFP Applications GFP is often used as a reporter of gene or protein expression. [...]

Jurkat cells were used to analyze cell cycle kinetics following treatment with the cell-cycle-arresting drug etoposide.  Etoposide is designed to arrest the cells at the G2 phase of the cell cycle. Jurkat cells were incubated with media only (control) or etoposide (0.06 µM, 0.12 µM) for 24 hours. Control and drug-treated cells were ethanol fixed and stained with cell cycle propidium iodide reagent. For each sample, 20 µl of cell sample (at ~4 x 106 cells / mL) was loaded into a Cellometer imaging chamber, inserted into the Vision CBA Analysis System, and imaged in both bright field and fluorescence. [...]

Introduction One of the most common and popular methods for cell cycle detection is the use of fluorescence-based dyes. There are a number of fluorescent-based dyes that are capable of binding to double stranded DNA upon cell fixation. Propidium iodide (PI) and DAPI are two such dyes. Since the amount of bound fluorescent dye is directly proportional to the amount of DNA present within a cell, these dyes can be used to detect the cell cycle within a population of cells. How it works: As the cells are going through the cell cycle, the amount of DNA that is contained [...]

Calcein AM (Calcein acetoxymethyl ester) is a non-fluorescent compound that passively enters cells. In metabolically active cells, Calcein AM is converted by cytosolic esterases into green fluorescent Calcein. The fluorescent Calcein is retained by live cells with intact membranes. Only cells possessing active cytosolic esterases fluoresce green. This allows for quick and easy detection of metabolically-active (vital) cells in a sample. […]