Molecular cloning and characterization of kiss1 in Brandt's voles (Lasiopodomys brandtii)

Kisspeptin, encoded by kiss1, has been regarded as a major modulator of mammalian puberty and fertility due to its stimulation on GnRH. Brandt's vole is one of the main pest species on the Inner Mongolian steppes for its striking reproductive capacity and kiss1 is a key candidate gene related to reproductive regulatory cascades. In this study, kiss1 cDNA was cloned from the hypothalamus of Brandt's voles and kiss1 mRNA levels were investigated in different tissues, and at different developmental stages, using high-throughput real-time PCR. The full-length kiss1 cDNA was 682 bp, containing an ORF of 405 bp, encoding 134 amino acids with a conserved kisspeptin-10 region. Kiss1 mRNA was specifically expressed in ovary, testicle, small intestine, kidney, liver and hypothalamus tissues, and was undetectable in other tissues, including pituitary, heart, adrenal gland, bladder and uterus. Sexual organs of both male and female voles enter a period of rapid development in the postnatal 4 weeks and reach or approach sexual maturity by 8 weeks after birth. Kiss1 mRNA levels in the hypothalamus did not show a significant difference between week 2 and week 4, indicating kiss1 mRNA levels may not be related to the rapid growth of the sexual organs in early developmental stages. Kiss1 transcripts significantly increased in both sexes 8 weeks after birth, and then were maintained at high levels in adults, indicating its possible role in the onset of puberty and maintaining of reproductive activity. These results are helpful to further the study of kiss1 function in reproductive regulation of Brandt's voles.