The Human Magel2 Gene and Its Mouse Homologue Are Paternally Expressed and Mapped to the Prader-Willi Region

Prader-Willi syndrome (PWS) is a complex neurogenetic disorder. The phenotype is likely to be a contiguous gene syndrome involving genes which are paternally expressed only, located in the human 15q11-q13 region. Four mouse models of PWS have been reported but these do not definitively allow the delineation of the critical region and the associated genes involved in the aetiology of PWS. Moreover, targeted mutagenesis of mouse homologues of the human candidate PWS genes does not appear to result in any of the features of PWS. Therefore, the isolation of new genes in this region remains crucial for a better understanding of the molecular basis of PWS. In this manuscript, we report the characterization of MAGEL2 and its mouse homologue Magel2. These are located in the human 15q11-q13 and mouse 7C regions, in close proximity to NDN / Ndn. By northern blot analysis we did not detect any expression of MAGEL2 / Magel2 but by RT-PCR analysis, specific expression was detected in fetal and adult brain and in placenta. Both genes are intronless with tandem direct repeat sequences contained within a CpG island in the 5'-untranscribed region. The transcripts encode putative proteins that are homologous to the MAGE proteins and NDN. Moreover, MAGEL2 / Magel2 are expressed only from the paternal allele in brain, suggesting a potential role in the aetiology of PWS and its mouse model, respectively.