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Jeff Bachant
Associate Professor of Cell Biology
Email: jeffrey.bachant@ucr.edu
Mitosis is a precisely regulated event during which equivalent
sets of chromosomes are partitioned between mother and daughter cells.
Research in this lab is focused on the mechanisms that ensure accurate
mitotic chromosome transmission and that make mitotic entry responsive
to stressful contingencies. One area of study is to elucidate how
replicated pairs of chromosomes are physically held together, or cohesed,
until the onset of chromosome segregation. Cohesive linkages between sister
chromatids are thought to enable chromatid pairs to achieve bipolar attachment
to the mitotic spindle. Centromeric regions of chromosomes appear
to be specialized sites of sister chromatid association, but the processes
that control this aspect of centromere function are not well understood.
We are utilizing the budding yeast S. cerevisiae to investigate how cohesion
is regulated at centromeres through the analysis of mutants that disrupt
chromatid associations at centric regions. Other projects are focused
on understanding how chromosome segregation is delayed following activation
of the checkpoint pathways that allow cells to respond to DNA damage or
blocks to DNA replication. In S. cerevisiae, DNA damage checkpoints
prevent chromosome segregation by blocking cells in a pre-anaphase state.
Analysis of this response may illuminate regulatory pressure points controlling
mitotic spindle function and the timing of chromosome segregation.
Representative Publications:
- Sanchez, Y., Bachant, J., Wang, H., Hu, F., Liu, D., Tetzlaff, M. and Elledge, S.J. (1999) Control of the DNA damage checkpoint by Chk1 and Rad53 protein kinases through distinct mechanisms. Science 286: 1166-1171.
- Jones SH, J Bachant, AR Castillo, TH Giddings and M Winey (1999) Yeast Dam1p is required to maintain spindle integrity during mitosis and interacts with the Mps1 kinase. Mol. Biol. Cell 10: 2377-2391.
- Desany, B., Alcasabas, A., Bachant, J. and Elledge, S.J. (1998) Recovery from DNA replicational stress is the essential function of the S-phase checkpoint pathway. Genes & Dev. 12: 2956-2970.
Manuscripts submitted or in preparation:
- Bachant J, A. Alcasabas, Y. Blat, N Kleckner and SJ Elledge. A role for the SUMO-1 isopeptidase Smt4 and DNA Topoismerase II in control of centromeric cohesion. Under revision.
- Alcasabas, AA, AJ. Osborn, J Bachant, F Hu, PJH. Werler, K Bousset, K Furuya, JFX Diffley, A Carr, and SJ Elledge. Mediator of the DNA Replication Checkpoint, MRC1, Transduces DNA Replication Stress Signals to Activate Rad53. Submitted.
- Bachant J, Y. Li, A. Alcasabas, and SJ Elledge. Centromere function and inhibition of origin firing are required for pre-anaphase spindle integrity during budding yeast S phase checkpoint arrest. In preparation.
- Li, Y. Bachant, J., Alcasabas, AA, and SJ Elledge. The mitotic spindle communicates to the kinetochore through transfer of the Ask1 protein. In preparation.
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