SPECIFIC ALU BINDING-PROTEIN FROM HUMAN SPERM CHROMATIN PREVENTS DNA METHYLATION

A protein from human sperm nuclei that specifically binds to Alu DNA r epeats has been purified. The specific DNA binding site of this protei n within the Alu sequence has been mapped by methylation interference and electrophoretic mobility shift assays. This sperm Alu binding prot ein selectively protects Alu elements from methylation in vitro and ma y be responsible for the unmethylated state of Alu sequences in the ma le germ line resulting in a parent-specific differential inheritance o f Alu methylation.