THE CENTROMERES OF MAMMALIAN CHROMOSOMES

The secrecy of the nature of the centromere-kinetochore complex of mam mals is beginning to be betrayed. One can already firmly suggest that, among the other satellite DNAs which are a subset of the constituants of the human centromeric regions, the alpha satellite is probably con tributing to the function of the centromere. The physical structure of the centromere-kinetochore complex is variable from one chromosome to the other and, moreover, prone to extreme polymorphism. Interactions between DNA and some of the proteins of the complex have been demonstr ated. One still does not know, however, why centromeric regions remain compact all along the cell cycle, why they are restricted in recombin ation and if they contain any gene. Centromere dysfunction is associat ed with a number of pathologies in man (aneuploidies, cancers...). A n umber of important questions concerning their structure and function r emain, however, unanswered.