The genome has a non-random spatial distribution in the cell nucleus. In 
Schizosaccharomyces pombe, it has been shown that the centromeres, telomeres and 
the mating-type region localize to the nuclear membrane (NM), the former by 
attaching to the spindle pole body (SPB). In addition, reporter genes inserted 
into these areas are transcriptionally repressed because of the formation of 
specialized chromatin structures. Performing live cell analysis we found that in 
a wild-type strain the mating-type region was positioned in the proximity of the 
SPB, the location where the pericentromeric heterochromatin is also found. In a 
strain lacking the histone methyltransferase Clr4, crucial for the formation of 
heterochromatin, the mating-type region had a random localization in the 
nucleus. Moreover, in a strain in which the two boundary elements IR-L and IR-R 
had been deleted, the mating-type region was displaced from its position at the 
proximity of the SPB, but remained in the vicinity of the NM. Moreover, in all 
investigated strains with silencing deficiencies the distance between the 
mating-type region and the SPB increased. This result indicates a correlation 
between transcriptional derepression and displacement of the region. Two 
different models of how the mating-type chromatin is organized in the nucleus 
are discussed.