Green fluorescent protein (GFP), a 27 kDa protein derived from the jellyfish Aequorea victoria, emits green light (emission peak at a wavelength of 509 nm) when excited byblue light (excitation peak at a wavelength of 395 nm). Green Fluorescent Protein (GFP) has become an invaluable tool in cell biology research, since its intrinsic fluorescence can be visualized in living cells.

Human elongation factor-1 alpha (EF-1 alpha) is a constitutive promoter of human origin that can be used to drive ectopic gene expression in various in vitro and in vivo contexts. EF-1 alpha (or EF1a) is often useful in conditions where other promoters (such as CMV) have diminished activity or have been silenced (as in embryonic stem cells).