M33, A MAMMALIAN HOMOLOG OF DROSOPHILA POLYCOMB LOCALIZES TO EUCHROMATIN WITHIN INTERPHASE NUCLEI BUT IS ENRICHED WITHIN THE CENTROMERIC HETEROCHROMATIN OF METAPHASE CHROMOSOMES
G. Wang et al., M33, A MAMMALIAN HOMOLOG OF DROSOPHILA POLYCOMB LOCALIZES TO EUCHROMATIN WITHIN INTERPHASE NUCLEI BUT IS ENRICHED WITHIN THE CENTROMERIC HETEROCHROMATIN OF METAPHASE CHROMOSOMES, Cytogenetics and cell genetics, 78(1), 1997, pp. 50-55
We have raised a monoclonal antibody (MoAb), MAC 402, to the mouse M33
protein, a mammalian homologue of the Drosophila Polycomb protein. MA
C 402 recognises a band of 59.7 kDa by Western blot analysis and gives
rise to two types of staining pattern within interphase nuclei. Surpr
isingly, at metaphase, M33 protein is enriched within centromeric hete
rochromatin. This pattern is also seen for the product of the bmi-1 ge
ne, which is a homologue of the Drosophila Polycomb-group (Pc-G) gene
Posterior sex combs. We speculate as to the reasons for this relocalis
ation of mammalian Pc-G gene products to the centromere at metaphase a
nd its implication for the cell-to-cell inheritance of the states of g
ene repression that are conferred by this highly conserved group of ge
nes.