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Advertisement: Thesis talk. Rosenstiel Penthouse. Friday 1:30 PM. Signaling and cell cycle in bacteria. Jamie Foti* Dan Ferullo* Nicky Persky** Vincent Sutera. *MCB grad student **Biophysics grad student. Replication(“Intra-S”) checkpoint response. DNA damage. “signal”.
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Advertisement: Thesis talk. Rosenstiel Penthouse. Friday 1:30 PM Signaling and cell cycle in bacteria Jamie Foti* Dan Ferullo* Nicky Persky** Vincent Sutera *MCB grad student **Biophysics grad student
Replication(“Intra-S”) checkpoint response DNA damage “signal” obgE (Ras-related G protein) Increased repair capacity Cell cycle arrest
Why is ObgE essential for viability? Depletion of ara regulated ObgE: (DAPI staining): Average c=20! • ObgE is required for chromosome segregation, a process not well understood in prokaryotes • Localization of specific chromosome regions via GFP-fusions to site-specific DNA binding protein show persistent cohesion at the terminus of replication
ObgE localization (LB growth) Green = ObgE Blue = DAPI (DNA) Pink = colocalization Helical structure similar to actin MreBrequired for chromosome segregation Does ObgE regulate engagement of chromosome with MreB filament?
Projects • Biochemistry: cofactors, modulation of GTP/GDP affinity of ObgE, structure, mass spectrometry analysis of interactors • Cell Biology: localization of ObgE, organization of replisome and actin filament; cell cycle effects • Molecular genetics: mutants affecting nucleotide states, genetic suppressors, molecular targets • Physiology: relationship to other regulatory pathways
Replication fork repair and genetic instability Deani Cooper Bethany Dutra Tracey Seier* Houra Merrikh* *MCB grad student
b PolIII DnaKJ g DnaB helicase DnaG primase block A template switch mechanism for replication fork repair See: Goldfless et al. 2006 Molecular Cell 21: 595
b Helicase PolIII g DnaKJ DnaB helicase DnaG primase block DnaB helicase remains loaded See: Goldfless et al. 2006 Molecular Cell 21: 595
b Helicase DnaB helicase DnaG primase block See: Goldfless et al. 2006 Molecular Cell 21: 595
b Helicase DnaB helicase DnaG primase block See: Goldfless et al. 2006 Molecular Cell 21: 595
b Helicase DnaB helicase DnaG primase block See: Goldfless et al. 2006 Molecular Cell 21: 595
b Helicase DnaB helicase DnaG primase block See: Goldfless et al. 2006 Molecular Cell 21: 595
Template switch b Helicase Pol DnaB helicase DnaG primase block See: Goldfless et al. 2006 Molecular Cell 21: 595
Pol Endonuclease DnaB helicase DnaG primase block Holliday junction Helicase b See: Goldfless et al. 2006 Molecular Cell 21: 595
Helicase b Pol Endonuclease DnaB helicase DnaG primase block See: Goldfless et al. 2006 Molecular Cell 21: 595
PolIII g DnaB helicase DnaG primase block Polymerase reassembled b Fork is repaired and block is bypassed FIRST RESPONDER to replication difficulties Template switches at site of repeats leads to genetic rearrangements
Projects • Biochemistry: changes in replisome after fork arrest? Purification /characterization of repair factors • Molecular genetics: mutants affecting survival to replication inhibitors • Cell Biology: How is replication fork remodeled after arrest? Is chromosome structure changed?
If interested contact me: • Lovett@brandeis.edu • 736-2497 • Thursday (ex. 10:30-12:30); Friday 10:30-1