Expression analysis of AK003491, an imprinted noncoding RNA, during mouse development.

The Dlk1-Dio3 imprinted domain on mouse chromosome 12qF1 contains three paternally expressed protein-coding genes and multiple maternally expressed long or short noncoding RNA genes. All these imprinted genes are regulated by IG-DMR located between Dlk1 and Meg3/Gtl2. Recently, several novel imprinted noncoding RNAs were identified in the intergenic region of this domain, although the exact number of imprinted genes within the region is unclear. Here, we report that a novel noncoding RNA, AK003491, located between Meg3/Gtl2 and Meg8, is maternally expressed in E15.5 brain, tongue, heart, lung, liver and kidney tissues. In situ hybridization analysis at E15.5 shows AK003491 is predominantly expressed in forebrain, tongue, thymus, somites, lung and liver. Quantitative real-time RT-PCR analysis confirms this expression pattern and detects highest expression in tongue. While the AK003491 expression pattern at postnatal day 1 is similar to E15.5, AK003491 expression at postnatal day 30 is mainly restricted to the brain. These results expand the number of known imprinted long noncoding RNAs in this domain, and contribute to further investigation of their regulatory mechanism and function.