BIOL 230W Lecture Notes - Lecture 21: S Phase, Cdc6, Apoptosis
Document Summary
Chromosomal missegregation occurs if proteins involved with signals are mutated. Few inhibitors produced cannot successfully keep apc turned on: anaphase occurs. Severe mutations severe aneuploidy cell death. Minor mutations minor aneuploidy (chromosomal instability) cell viability (possibly cancer: chromosomal instability is a common characteristic of tumorigenesis. Chemotherapeutic drugs target microtubules: results in the production of checkpoint signals, typically prevents cell (tumor) from dividing. Chronic activation of signal (several weeks of chemotherapy treatment) can result in three adaptations: exit mitotic arrest and enter g1 without proper cytokinesis. Aneuploidy cells survive and continue to divide: exit mitosis and death, exit mitosis and apoptosis. Orc (origin of replication complex): proteins that recognize origin of replication: typically, a/t rich regions of genome (weaker bonds) Cdc6, cdt1, mcm recruited to complex: mcm: helicase enzyme, targets hydrogen bonds. Dna sequence and chromatin play a role in orc recognition: euchromatin (loose) required for replication to occur. Orc activated to bind dna only in g1 in eukaryotes.
