Stem Cells

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).

GPR49/LGR5 (G protein-coupled receptor 49/leucine-rich repeat-containing G protein-coupled receptor 5) is also known by the names FEX, GPR67, GRP49, HG38, and MGC117008). It is an orphan receptor and structurally related to members of the mammalian large transmembrane glycoprotein hormone receptor family (FSH-R, TSH-R, and LH-R).

Human stem cell research has proved a controversial topic, but the latest developments could alter the debate significantly.