Generation of Oxtr cDNA^HA‐Ires‐Cre Mice for Gene Expression in an Oxytocin Receptor Specific Manner

Abstract

The neurohypophysial hormone oxytocin (OXT) and its receptor (OXTR) have critical roles in the regulation of pro-social behaviors, including social recognition, pair bonding, parental behavior, and stress-related responses. Supporting this hypothesis, a portion of patients suffering from autism spectrum disorder have mutations, such as single nucleotide polymorphisms, or epigenetic modifications in their OXTR gene. We previously reported that OXTR-deficient mice exhibit pervasive social deficits, indicating the critical role of OXTR in social behaviors. In the present study, we generated Oxtr cDNA(HA)-Ires-Cre knock-in mice, expressing both OXTR and Cre recombinase under the control of the endogenous Oxtr promoter. Knock-in cassette of Oxtr cDNA(HA)-Ires-Cre consisted of Oxtr cDNA tagged with the hemagglutinin epitope at the 3' end (Oxtr cDNA(HA)), internal ribosomal entry site (Ires), and Cre. Cre was expressed in the uterus, mammary gland, kidney, and brain of Oxtr cDNA(HA)-Ires-Cre knock-in mice. Furthermore, the distribution of Cre in the brain was similar to that observed in Oxtr-Venus fluorescent protein expressing mice (Oxtr-Venus), another animal model previously generated by our group. Social behavior of Oxtr cDNA(HA)-Ires-Cre knock-in mice was similar to that of wild-type animals. We demonstrated that this construct is expressed in OXTR-expressing neurons specifically after an infection with the recombinant adeno-associated virus carrying the flip-excision switch vector. Using this system, we showed the transport of the wheat-germ agglutinin tracing molecule from the OXTR-expressing neurons to the innervated neurons in knock-in mice. This study might contribute to the monosynaptic analysis of neuronal circuits and to the optogenetic analysis of neurons expressing OXTR.

Diversity of oxytocin neurones: Beyond magno‐ and parvocellular cell types?

“…Therefore, it is likely that magnOT form collaterals of axons, allowing them to project to various forebrain regions and the posterior pituitary simultaneously. This assumption can be further clarified by the application of Cre‐dependent viral vectors to transgenic animals expressing the Cre‐recombinase in OT neurones or OTR‐expressing neurones in mice and rats (recently generated and characterised; V. Grinevich, K. Schoenig, D. Bartsch and M. Eliava, unpublished data).…”

Oxytocin and vasopressin in the rodent hippocampus

“…First, Oxtr expression is detected in mouse hippocampus by in vitro receptor autoradiography, 62 immunohistochemistry, 63 and ISH. 49,50,57,58 Second, two transgenic mouse lines carrying fluorescent reporters linked to Oxtr expression display Oxtr throughout the dentate gyrus (DG), CA3, CA2 and CA1 regions, with abundant expression noted in CA2/CA3, 64,65 as is seen with immunohistochemistry. 63 Cell type and region-specific differences exist in mouse hippocampal Oxtr distribution.…”

The role of oxytocin in regulation of appetitive behaviour, body weight and glucose homeostasis

“…OXTR receptors (OXTR) are widely distributed and largely overlap in areas linked to the control of energy balance in both mice and rats, namely the basal ganglia (eg, nucleus accumbens [NAcc] and central amygdala) (mouse/rat), hypothalamus (ARC, MPA and ventromedial hypothalamus [VMH]) (mouse/rat), midbrain VTA (mouse/rat), hindbrain PBN (mouse), AP (mice), dorsal motor nucleus of the vagus (DMV) (rat), NTS (mouse/rat) and spinal cord (mouse/rat). OXTR are also found in the SON and PVN of OXT neurones in the rat, although it is unclear whether this is the case in the mouse.…”