ISOLATION OF A POTENTIALLY FUNCTIONAL Y-BOX PROTEIN (MSY-1) PROCESSEDPSEUDOGENE FROM MOUSE - EVOLUTIONARY RELATIONSHIPS WITHIN THE EF1(A) DBPB/YB-1 GENE FAMILY/

A processed pseudogene from Mus musculus, designated psi MSY-2, was ob tained from a genomic library by screening with a MSY-1 cDNA (encoding mouse Y-box factor 1) probe. Mouse psi MSY-2 is intronless and has an ORF with an in-frame translational stop. The pseudogene has repeat se quences at the 5' and 3' boundaries, suggestive of an origin as a retr oposon, and exhibits mutagenesis of CpG residues at a frequency at lea st tenfold higher than predicted from random mutagenesis. This indicat es that 'repeat-induced point mutagenesis' or ripping has occurred. We find that the mouse genome contains many DNA sequences with homology to a cDNA encoding the DNA-binding domain of the Y-box proteins. We es timate that there are at least 15 copies per haploid genome.