Using transgenic mouse models to study oxytocin's role in the facilitation of species propagation

Abstract

Oxytocin and its receptor are important for a wide range of effects, from social memory to uterine contractions. It is an evolutionarily well-conserved hormone that is particularly important in social and gregarious animals. Research on small mammals has yielded a rich literature on oxytocin's many functions. Recently a new tool has been created that has furthered our understanding of oxytocin's role in behavior: transgenic mice that lack either the ability to synthesize oxytocin or the oxytocin receptor itself. The study of these lines, while still in its infancy, is already bearing fruit and offers the promise of insight into some human disorders characterized by aberrant social behavior.

Figure 1

Controlling the oxytocin receptor (Oxtr) gene expression by Cre recombinase-mediated DNA recombination. The floxed oxytocin receptor gene allele is introduced by homologous recombination. The Camk2a promoter drives Cre recombinase (Cre) expression in transgenic mice relatively specifically in the forebrain (indicated by blue beta-galactosidase histochemistry). By crossing the floxed mice (showing normal oxytocin receptor in vitro receptor binding in upper left autoradiogram) with this Cre transgenic line, progeny are produced in which the conditional allele is inactivated only in the forebrain (lower autoradiogram). Therefore, oxytocin receptor expression still remains in other tissues, such as the mammary glands. Cre recombinase recognizes two loxP sites (chevrons) and eliminates the floxed oxytocin receptor exons. Adapted from (Lee et al., 2008b).