Two novel genes in the center of the 11p15 imprinted domain escape genomicimprinting

We previously reported the isolation of a 2.5 Mb tumor-suppressing subchrom osomal transferable fragment (STF) from human chromosome 11p15 and the iden tification of nine known genes and four novel genes within this STF, We now report the isolation of two novel cDNAs, designated here as TSSC4 and TSSC 6(tumor-suppressing STF cDNA 4 and 6), located within the STF, TSSC4 and TS SC6 encode predicted proteins of 329 and 290 amino acids, respectively, wit h no close similarity to previously reported proteins. TSSC4 and TSSC6 are both located in the center of a 1 Mb imprinted domain, which contains the i mprinted genes TSSC3, TSSC5, p57(KIP2), K(V)LQT1, ASCL2, IGF2 and H19, Howe ver, we found that neither TSSC4 nor TSSC6 was significantly imprinted in a ny of the fetal or extra-embryonic tissues examined. Based on this result, the imprinted gene domain of 11p15 appears to contain at least two imprinte d subdomains, between which TSSC4 and TSSC6 substantially escape imprinting , due either to lack of initial silencing or to an early developmental rela xation of imprinting.