Spindle pole body duplication: a model for centrosome duplication?

The yeast spindle pole body (SPB) is the functional equivalent of the centr osome and forms the two poles of the mitotic spindle. Before mitosis, both SPBs and centrosomes are present as single copies and must be duplicated to form the bipolar spindle. SPB components have been identified using a comb ination of biochemistry and genetics, and their role during SPB duplication has been analysed using temperature-sensitive mutants. In this article, we describe structural aspects of SPB duplication and their possible relation ship to centrosome duplication.