Alternative polyadenylation signals and promoters act in concert to control tissue-specific expression of the Opitz Syndrome gene MID1
1 Max-Planck Institute for Molecular Genetics, Berlin-Dahlem, Germany
2 Institute of Biochemistry, University Innsbruck, Austria
3 ALTANA Pharma AG, Preclinical Research Bioinformatics, Konstanz, Germany
4 Department of Dermatology, Charité-Hospital, Berlin, Germany
5 Department of Neuroscience and Pathology, College of Medicine, University of Dundee, Dundee, UK
BMC Molecular Biology 2007, 8:105 doi:10.1186/1471-2199-8-105Published: 15 November 2007
Mutations in the X-linked MID1 gene are responsible for Opitz G/BBB syndrome, a malformation disorder of developing midline structures. Previous Northern blot analyses revealed the existence of at least three MID1 transcripts of differing lengths.
Here we show that alternative polyadenylation generates the size differences observed in the Northern blot analyses. Analysis of EST data together with additional Northern blot analyses proved tissue-specific usage of the alternative polyadenylation sites. Bioinformatic characterization of the different 3'UTRs of MID1 revealed numerous RNA-protein interaction motifs, several of which turned out to be conserved between different species. Furthermore, our data suggest that mRNA termination at different polyadenylation sites is predetermined by the choice of alternative 5'UTRs and promoters of the MID1 gene, a mechanism that efficiently allows synergistic function of 5' and 3'UTRs.
MID1 expression is tightly regulated through concerted action of alternative promoters and alternative polyadenylation signals both during embryonic development and in the adult.