The oocyte-specific methylated region of the U2afbp-rs/U2af1-rs1 gene is dispensable for its imprinted methylation

Imprinted genes harbor discrete regions which are differentially methylated in gametes; usually the final differential methylation patterns in adults are established during embryogenesis through modifications of the initial m ethylation patterns in gametes. Previous reports have shown that a 200-bp r egion termed region II within the CpG island of the mouse imprinted U2afbp- rs gene is methylated in oocytes but not in sperm, suggesting that this reg ion is a center for the propagation of methylated CpGs on the maternal alle le and is also a candidate for an imprinting control element. To determine whether region II is required for the imprinted methylation of this gene at the endogenous locus, we generated mice carrying a deletion of this region . We herein show that parental methylation differences still exist in the C pG island on the region II-deleted allele. These findings suggest that regi on II is dispensable for the imprinted methylation Of the U2afbp-rs gene. ( C) 2000 Academic Press.