Cre (Cyclization recombination enzyme) is a member of the large family of recombinases. Cre recognizes Lox site loxP, a 34 bp sequence motif from the PI bateriophage. If a DNA segment is flanked by two loxP sites in the same orientation, Cre neatly excises the segment (for later degradation) leaving a single remaining loxP site in the DNA molecule. The Cre/Lox system was first developed in the late 1980's to artificially manipulate gene expression and extensive reviews of the system exist (1). Because the Cre/lox system works in almost any type of cell, it has proven extremely useful, it has been extensively used and there are now numerous and stable animal, plant, and bacterial stocks that already contain the Cre gene driven by various ubiquitous, tissue-specific and/or inducible promoters.
Immunohistochemistry: Cre Antibody
Welsbie’s group used Cre antibody in their functional genomic screenings of mediators of retinal ganglion death to define the key pathways in glaucoma and blindness (2). Cre antibody was also employed in stem cell studies on endocrine and exocrine cell compartments in the development of the pancreas (3). That group found an unknown regulatory pathway and Notch-dependent coordination between endocrine and ductal progenitor cell groups. Banares’ group relied upon the Cre antibody to develop their novel, pan-neuronal Cre-transgenic line enabling the controlled and conditional deletion of genes specifically in neurons, the CNS, and their progenitors (4).
