Tg(YACW408A5)1952Ricc

An 800kb yeast artificial chromosome (YAC) designated W408A5, which contained C57BL/6 distal chromosome 7 sequence from the Cars to Th gene, and including imprinting center(IC2 which contains Cdkn1c (P57) and Kcnq1) and is syntenic to human chromosome 11p15.5, was modified by addition of 2 copies of the Neo-selection cassette. The construct was introduced into 129/Sv ES cells by yeast spheroplast fusion. After maternal transmission of the transgene, most maternally expressed genes of the IC2 region (Phdla2, Slc22a18, Cdkn1c and Kcnq1) show 30-60% increased expression in the placenta relative to wild-type and equivalent or slightly reduced expression after paternal transmission. With paternal transmission, paternally expressed gene Kcnq1ot1 shows 2-fold increased expression over wild-type or after maternal transmission. Ascl2 expression (maternally expressed) is increased 2-fold after maternal or paternal transmission, while Tssc4 expression is increased 2-fold after maternal and by ~33% after paternal transmission. Imprinting of these 2 genes is not reproduced by the transgene. Expression of Cdkn1c and Kcnq1ot1 in the embryo is comparable to the placental expression (J:66461, J:96366)