Development. Cell division. Neurobiology. Why do we work on yeast?. Yeast has a long history of serving mankind. Yeast satisfy important characteristics of a model organism.
Maintains circular plasmids and mini chromosomes
Homologous (integrative) transformation very efficient
HeLa cell: metaphase
PtK1 cell: anaphase
Aberrations lead to chromosome loss
associated with cancers and birth defects
of a PtK1 Chromosome
Kinetochores are essential for chromosome segregation
Kinetochores- protein-DNA complex
built at the centromeric
region of the chromosome
Function- Physical linkage between
DNA and microtubules
Structure- Integrate DNA binding and
microtubule binding proteins
EM by Lynne Cassimeris
of cell division.
of DNA that do not encode
genes i.e. centromeres, telomeres
and origins of replication?
Lee Hartwell 2001 Nobel Prize
Figure 6. A pathway of gene controlled events in the S. cerevisiae cell cycle. Numbers refer to cdc genes.
Abbreviations are: iDS, initiation of DNA synthesis, DS, DNA synthesis, mND, medial nuclear
division; lND, late nuclear division; BE, bud emergence; NM, nuclear migration; CK, cytokinesis;
CS cell separation; MF mating factor. Reprinted from ref 7 with permission.
-DNA repair and recombination, DNA damage check point
Mad and Bub-(budding in presence of MT poison)
Sec-(cells became dense) secretory pathway, protein sorting
-GTPases, GAPs, adaptors
Swi/Snf- (growth defect on nonfermentable carbon source) glucose derepression
Chromatin remodeling factors
Kinetochores are clustered at the ends
the cohesin cylinder
Proposed Path of Centromere DNA in a Eukaryotic Kinetochore: C-loop