Scm3, an essential Saccharomyces cerevisiae centromere protein required for G 2 /M progression and Cse4 localization
A universal mark of centromeric chromatin is its packaging by a variant of histone H3 known as centromeric H3 (CenH3). The mechanism by which CenH3s are incorporated specifically into centromere DNA or the specialized function they serve there is not known. In a genetic approach to identify factors...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 104; no. 25; pp. 10571 - 10576 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
19.06.2007
|
Online Access | Get full text |
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Summary: | A universal mark of centromeric chromatin is its packaging by a variant of histone H3 known as centromeric H3 (CenH3). The mechanism by which CenH3s are incorporated specifically into centromere DNA or the specialized function they serve there is not known. In a genetic approach to identify factors involved in CenH3 deposition, we screened for dosage suppressors of a temperature-sensitive
cse4
allele in
Saccharomyces cerevisiae
(Cse4 is the
S. cerevisiae
CenH3). Independent screens yielded ORF YDL139C, which we named
SCM3
. Dosage suppression by
SCM3
was specific for alleles affecting the histone fold domain of Cse4. Copurification and two-hybrid studies showed that Scm3 and Cse4 interact
in vivo
, and chromatin immunoprecipitation revealed that Scm3, like Cse4, is found associated with centromere DNA. Scm3 contains two essential protein domains, a Leu-rich nuclear export signal and a heptad repeat domain that is widely conserved in fungi. A conditional
scm3
allele was generated to allow us to deplete Scm3. Upon Scm3 depletion, cells undergo a Mad2-dependent G
2
/M arrest, and centromere localization of Cse4 is perturbed. We suggest that
S. cerevisiae
Scm3 defines a previously undescribed family of fungal kinetochore proteins important for CenH3 localization. |
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ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.0703178104 |