The imprinted lncRNA Peg13 regulates sexual preference and the sex-specific brain transcriptome in mice

Mammalian genomes include many maternally and paternally imprinted genes. Most of these are also expressed in the brain, and several have been implicated in regulating specific behavioral traits. Here, we have used a knockout approach to study the function of Peg13, a gene that codes for a fast-evolving lncRNA (long noncoding RNA) and is part of a complex of imprinted genes on chromosome 15 in mice and chromosome 8 in humans. Mice lacking the 3' half of the transcript look morphologically wild-type but show distinct behavioral differences. They lose interest in the opposite sex, instead displaying a preference for wild-type animals of the same sex. Further, they show a higher level of anxiety, lowered activity and curiosity, and a deficiency in pup retrieval behavior. Brain RNA expression analysis reveals that genes involved in the serotonergic system, formation of glutamatergic synapses, olfactory processing, and estrogen signaling-as well as more than half of the other known imprinted genes-show significant expression changes in Peg13-deficient mice. Intriguingly, these pathways are differentially affected in the sexes, resulting in male and female brains of Peg13-deficient mice differing more from each other than those of wild-type mice. We conclude that Peg13 is part of a developmental pathway that regulates the neurobiology of social and sexual interactions.