Fragile X mental retardation protein interacts with TDG

Fragile X syndrome is the most common form of inherited mental retardation disease, resulting from absent of expression of its disease gene FMR1. To s tudy the function of the fragile X mental retardation protein (FMRP) throug h protein/protein interaction, a mouse embryo cDNA library was screened by the yeast two-hybrid system. A clone was found to interact specifically wit h FMRP. The cDNA of this clone ( Genbank accession number af102875) encoded a protein highly homologous to human G/T mismatch-specific DNA thymine gly cosylase ( hTDG ). Interactions between various alternatively spliced FMRP isoforms and a series of mTDG deletion proteins were further studied in the yeast two-hybrid system and their interaction amino acid regions were dete rmined. Interaction between FMRP and TDG existed inside exon 13 of FMRP ( a mino acid residue 397-425) and around amino acid residue 122-346 of TDG. Th ese results will be helpful to the study of the biological role of FMRP.