ABSENCE OF IMPRINTING IN U2AFBPL, A HUMAN HOMOLOG OF THE IMPRINTED MOUSE GENE U2AFBP-RS

The mouse gene U2 auxiliary factor binding protein related sequence (U 2afbp-rs) has previously been shown to be genomically imprinted with m onoallelic expression from the paternal allele. To determine if the hu man homologue is imprinted and contains conserved structural features which regulate imprinting, we isolated genomic clones from a human P1- derived artificial chromosome (PAC) library that map to human chromoso me 5q22-31, a region syntenic to the proximal portion of mouse chromos ome 11 where U2afbp-rs resides. A genomic subclone was isolated which contained an open reading frame with high homology to the mouse gene. This subclone also maintained the intronless character of the mouse ge ne. A KpnI polymorphism within the open reading frame of the gene was found to occur in 21% (8/38) of the alleles tested from human placenta l tissue samples. RT-PCR analysis of human placentas using the KpnI po lymorphism to determine the parental origin of the alleles indicates b iallelic expression of the human chromosome 5 U2AFBPL gene. (C) 1996 A cademic Press, Inc.