Cl. Doe et al., THE FISSION YEAST CHROME DOMAIN ENCODING GENE CHP1-TUBULIN( IS REQUIRED FOR CHROMOSOME SEGREGATION AND SHOWS A GENETIC INTERACTION WITH ALPHA), Nucleic acids research, 26(18), 1998, pp. 4222-4229
In eukaryotes, the segregation of chromosomes is co-ordinated by the c
entromere and must proceed accurately if aneuploidy and cell death are
to be avoided. The fission yeast centromere is complex, containing hi
ghly repetitive regions of DNA showing the Characteristics of heteroch
romatin. Two proteins, Swi6p and Clr4p, that are associated with the f
ission yeast centromere also contain a chrome (chromatin organisation
modifier) domain and are required for centromere function. We have ana
lysed a novel fission yeast gene encoding a putative chrome domain cal
led chp1(+) (chromo domain protein in Schizosaccharomyces pombe). In t
he absence of Chp1p protein, cells are viable but show chromosome segr
egation defects such as lagging chromosomes an the spindle during anap
hase and high rates of minichromosome loss, phenotypes which are also
displayed by swi6 and clr4. A fusion protein between green fluorescent
protein (GFP) and Chp1p, like Swi6p, is localized to discrete sites w
ithin the nucleus. In contrast to Swi6p and Clr4p, Chp1p is not requir
ed to repress silent mating-type genes. We demonstrate a genetic inter
action between chp1(+) and alpha-tubulin (nda2(+)) and between swi6(+)
and beta-tubulin (nda3(+)). Chp1p and Swi6p proteins may be component
s of the kinetochore which captures and stabilizes the microtubules of
the spindle.