B. Goto et al., Cytoplasmic microtubular system implicated in de novo formation of a Rabl-like orientation of chromosomes in fission yeast, J CELL SCI, 114(13), 2001, pp. 2427-2435
Chromosomes are not packed randomly in the nucleus. The Rab1 orientation is
an example of the non-random arrangement of chromosomes, centromeres are g
rouped in a limited area near the nuclear periphery and telomeres are locat
ed apart from centromeres. This orientation is established during mitosis a
nd maintained through subsequent interphase in a range of species. We repor
t that a Rab1-like configuration can be formed de novo without a preceding
mitosis during the transition from the sexual phase to the vegetative phase
of the life cycle in fission yeast. In this process, each of the dispersed
centromeres is often associated with a novel Sad1-containing body that is
contacting a cytoplasmic microtubule laterally (Sad1 is a component of the
spindle pole body (SPB)). The Sad1-containing body was colocalized with oth
er known SPB components, Kms1 and Spo15 but not with Cut12, indicating that
it represents a novel SPB-related complex. The existence of the triplex st
ructure (centromere-microtubule-Sad1 body) suggests that the clustering of
centromeres is controlled by a cytoplasmic microtubular system. Accordingly
, when microtubules are destabilized, clustering is markedly reduced.