THE IPL GENE ON CHROMOSOME 11P15.5 IS IMPRINTED IN HUMANS AND MICE AND IS SIMILAR TO TDAG51, IMPLICATED IN FAS EXPRESSION AND APOPTOSIS

We searched for novel imprinted genes in a region of human chromosome 11p15.5, which contains several known imprinted genes. Here we describ e the cloning and characterization of the IPL (Imprinted in Placenta a nd Liver) gene, which shows tissue-specific expression and functional imprinting, with the maternal allele active and the paternal allele re latively inactive, in many human and mouse tissues, Human IPL is highl y expressed in placenta and shows low but detectable expression in fet al and adult liver and lung, Mouse IPL maps to the region of chromosom e 7 which is syntenic with human 11p15.5 and this gene is expressed in placenta and at higher levels in extraembryonic membranes (yolk sac), fetal liver and adult kidney, Mouse and human IPL show sequence simil arity to TDAG51, a gene which was shown to be essential for Fas expres sion and susceptibility to apoptosis in a T lymphocyte cell line. Like several other imprinted genes, mouse and human IPL genes are small an d contain small introns, These data expand the repertoire of known imp rinted genes and will be helpful in testing the mechanism of genomic i mprinting and the role of imprinted genes in growth regulation.