TY - JOUR
T1 - The synaptonemal complex protein, Zip1, promotes the segregation of nonexchange chromosomes at meiosis I
AU - Newnham, Louise
AU - Jordan, Philip
AU - Rockmill, Beth
AU - Roeder, G. Shirleen
AU - Hoffmann, Eva
PY - 2010
Y1 - 2010
N2 - Crossing over establishes connections between homologous chromosomes that promote their proper segregation at the first meiotic division. However, there exists a backup system to ensure the correct segregation of those chromosome pairs that fail to cross over.We have found that, in budding yeast, a mutation eliminating the synaptonemal complex protein, Zip1, increases the meiosis I nondisjunction rate of nonexchange chromosomes (NECs). The centromeres of NECs become tethered during meiotic prophase, and this tethering is disrupted by the zip1 mutation. Furthermore, the Zip1 protein often colocalizes to the centromeres of the tethered chromosomes, suggesting that Zip1 plays a direct role in holding NECs together. Zip3, a protein involved in the initiation of synaptonemal complex formation, is also important for NEC segregation. In the absence of Zip3, both the tethering of NECs and the localization of Zip1 to centromeres are impaired. A mutation in the MAD3 gene, which encodes a component of the spindle checkpoint, also increases the nondisjunction of NECs. Together, the zip1 and mad3 mutations have an additive effect, suggesting that these proteins act in parallel pathways to promote NEC segregation. We propose that Mad3 promotes the segregation of NECs that are not tethered by Zip1 at their centromeres.
AB - Crossing over establishes connections between homologous chromosomes that promote their proper segregation at the first meiotic division. However, there exists a backup system to ensure the correct segregation of those chromosome pairs that fail to cross over.We have found that, in budding yeast, a mutation eliminating the synaptonemal complex protein, Zip1, increases the meiosis I nondisjunction rate of nonexchange chromosomes (NECs). The centromeres of NECs become tethered during meiotic prophase, and this tethering is disrupted by the zip1 mutation. Furthermore, the Zip1 protein often colocalizes to the centromeres of the tethered chromosomes, suggesting that Zip1 plays a direct role in holding NECs together. Zip3, a protein involved in the initiation of synaptonemal complex formation, is also important for NEC segregation. In the absence of Zip3, both the tethering of NECs and the localization of Zip1 to centromeres are impaired. A mutation in the MAD3 gene, which encodes a component of the spindle checkpoint, also increases the nondisjunction of NECs. Together, the zip1 and mad3 mutations have an additive effect, suggesting that these proteins act in parallel pathways to promote NEC segregation. We propose that Mad3 promotes the segregation of NECs that are not tethered by Zip1 at their centromeres.
KW - Centromere
KW - Mad3
KW - Nondisjunction
KW - Spindle checkpoint
KW - Zip3
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U2 - 10.1073/pnas.0913435107
DO - 10.1073/pnas.0913435107
M3 - Article
C2 - 20080752
AN - SCOPUS:76249110367
SN - 0027-8424
VL - 107
SP - 781
EP - 785
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 2
ER -