Dual chromogenic reporter gene detection in mammalian cells with lacZ and arabinofuranosidase

A New Enzyme on the Block Originally patented for more industrial uses, namely the hydrolysis of plant material into fermentable sugars, α-L-arabinofuranosidase has been reconceived as a tool for the molecular biologist. Tsuchida et al. (p. 896) demonstrate that this enzyme (encoded by the abfA gene), when used in conjunction with a synthetic substrate, Z-ara, can be detected and visualized in a manner identical to the ubiquitous LacZ system. They have further shown that cotransfection of abfA and LacZ—the latter linked to a nuclear localization signal—into NIH 3T3 cells yielded clearly different and distinguishable staining patterns: a blue cytoplasm from the Z-ara substrate and a red-purple nucleus resulting from hydrolysis of Magenta-Gal, an X-gal analog. No cross-reactivity of substrates was seen. The absence of α-L-arabinofuranosidase or its natural substrates in mammalian cells creates a system with very low background, allowing it potentially to replace LacZ in assays where high levels of endogenou...