James L Resnick,

Fun fact: I am a habitual solver of the New York Times Sunday crossword puzzle. About 150 mammalian genes are subject to genomic imprinting, the selective silencing of one parent’s alleles. Most imprinted genes are found in clusters containing both maternally and paternally expressed genes. Prader-Willi syndrome and Angelman syndromes are clinically distinct neurodevelopmental disorders resulting from a cluster of imprinted genes located at 15q11-q13. Disruptions to paternal gene expression result in PWS, while disruption of the maternally expressed gene UBE3A leads to AS. At this locus two DNA elements, the PWS-IC and the AS-IC, are necessary for parent-of-origin allele identity and for parental-allele specific gene expression. Using engineered mutations in mice, we identified the molecular activity and development stage at which the PWS-IC functions. We also identified the mouse sequence orthologous to the AS-IC which enabled us to determine its molecular function. These novel mouse mutants also serve as disease models to better understand these two disorders.