THE MOUSE AND HUMAN HOMOLOGS OF DMC1, THE YEAST MEIOSIS-SPECIFIC HOMOLOGOUS RECOMBINATION GENE, HAVE A COMMON UNIQUE FORM OF EXON-SKIPPED TRANSCRIPT IN MEIOSIS

Genetic recombination in meiosis plays an important role in generating diversity of genetic information. In yeast an Escherichia coli RecA-l ike gene, DMC1, is expressed in meiotic prophase and its product co-lo calizes with Rad51 protein on zygotene chromosomes, We have cloned the mouse and human homologs of the yeast DMC1 gene, The predicted human and mouse DMC1 proteins showed 54.1% sequence identity with yeast Dmc1 protein, The domain II region, highly conserved in the E.coli RecA-li ke protein family, was also found in the mammalian DMC1 proteins, incl uding the two ATP binding motifs and DNA binding sites within the regi on, In situ hybridization analysis revealed expression of the mouse Dm c1 gene in testicular germ cells in meiosis; RT-PCR showed expression in embryonal ovaries, These findings suggest that DMC1 plays an import ant role in meiotic homologous recombination. From both the man and mo use we have isolated an alternative spliced form of Dmc1 cDNA (Dmc1-d) , which is deleted for a region between the two motifs involved in nuc leotide binding, Since the alternatively spliced Dmc1-d transcript was detected in both male and female germ cells, the encoded protein DMC1 -D may have a novel role in mammalian genetic recombination in meiosis .