Imprinting of mouse Kvlqt1 is developmentally regulated

Mouse distal chromosome 7 contains a cluster of at least five imprinted genes. The syntenic region in humans, at 11p15.5, has been implicated in several genetic disorders. Consistent with the imprinted status of the genes in the region, Beckwith-Wiedemann syndrome (BWS) and Wilms tumor are each associated with loss of maternal information. Also mapping to 11p15.5 are long QT and Jervell and Lange-Nielsen (JLN) syndromes. In contrast to BWS and Wilms tumor, these syndromes do not show any parent of origin bias. Recently positional cloning has identified KVLQT1 as the 11p15.5 gene responsible for increased susceptibility to long QT and JLN syndromes. Other studies associate KVLQT1 with BWS. Human KVLQT1 is paternally imprinted in embryos. In this study we present a contig and transcript map of distal mouse 7 and we physically and genetically map mouse Kvlqt1 to the region. Mouse Kvlqt1 is strongly expressed in heart, lung, gut, kidney and uterus. While its early developmental expression is maternal in origin, the paternal allele becomes increasingly active during development. Late juvenile and adult animals show complete biallelism, suggesting an explanation for the lack of parent of origin bias in JLN and long QT.