FUNCTIONAL ANALYSIS OF IMPRINTING MUTATIONS

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DESCRIPTION: (adapted from Applicant's Abstract): Mutations in the imprinting process in chromosome 15q11-q13 cause failure to switch the imprint of a 2 Mb region during parental gametogenesis, with Angelman or Prader-Willi syndrome (AS or PWS) arising, depending on the parental origin of the mutation. AS imprinting mutation patients have mutations in an element the P.I. suggests controls paternal to maternal (pat >mat) imprint switching in the female germline, while PWS families have mutations in the SNRPN promoter, which he suggests controls mat >pat imprint switching in the male germline. These AS and PWS mutations define a putative imprinting center (IC). The studies proposed here have three specific aims to test these hypotheses, by making mouse models of imprinting mutations: (1) Isolation and characterization of IC transcripts (pat >mat switch element, XX germline) and the Snrpn promoter (mat >pat switch element, XY germline), to test the role of these elements in imprint switching; (2) Target mutations into the mouse IC by homologous recombination in embryonic stem cells, to conclusively test the role hypothesized for these elements in imprint switching; (3) Examine the epigenotypic outcome for imprinted genes in the 2 Mb domain controlled by the IC, on expression and DNA methylation, from inheritance of imprinting mutations, and examine for phenotypic effects.