THE M31 GENE HAS A COMPLEX DEVELOPMENTALLY-REGULATED EXPRESSION PROFILE AND MAY ENCODE ALTERNATIVE PROTEIN PRODUCTS THAT POSSESS DIVERSE SUBCELLULAR-LOCALIZATION PATTERNS

HP1-like chromobox genes comprise an evolutionarily conserved family o f genes that encode components of centromeric heterochromatin. In orde r to investigate the role of the murine HP1-like gene, M31, in heteroc hromatin formation we have isolated its gene and characterised its tra nscripts and protein products. PCR products that represent M31 transcr ipts were detected at the one-cell stage and were maternal in origin. Maternal provision of M31 transcripts may reflect a need for M31 in th e formation of a functional centromere in order that there is proper s egregation of chromosomes during the early cleavage divisions; studies in fission yeast and Drosophila have suggested a crucial role for HP1 -like genes in centromere function. There are three protein products e ncoded by the M31 gene. Surprisingly, the two smaller products are fou nd almost exclusively in the cytoplasm. (C) 1998 Wiley-Liss, Inc.