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M267 Lecture 1, Cell Cycle February 7, 2005. The two “musts” of cell division: Cells must replicate their DNA Cells must segregate the DNA to the progeny cells in mitosis. Mitotic cell. INTERPHASE. interphase cell. Mitotic cell. interphase cell. Mitotic cell.
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M267 Lecture 1, Cell Cycle February 7, 2005
The two “musts” of cell division: Cells must replicate their DNA Cells must segregate the DNA to the progeny cells in mitosis
interphase cell Mitotic cell
interphase cell Mitotic cell Label with 32P, autoradiograph immediately
interphase cell Mitotic cell Label with 32P, add colchicine, wait 2 hrs. Label with 32P, autoradiograph immediately
interphase cell Mitotic cell Label with 32P, add colchicine, wait 2 hrs. Label with 32P, add colchicine, wait 6 hrs. Label with 32P, autoradiograph immediately
DNA Synthesis Gap M M
Gap DNA Synthesis Gap M M
Gap DNA Synthesis Gap M M S G2 G1
Some interphase cells labeled, some not 30 Minute Pulse with 3H-TdR, Autoradiograph Immediately
No labeled mitoses 30 Minute Pulse with 3H-TdR, Autoradiograph Immediately
30 Minute Pulse with 3H-TdR, add colchicine, autoradiograph 5 Hours Later
An increase in number of labeled and unlabeled mitotic cells 30 Minute Pulse with 3H-TdR, add colchicine, autoradiograph 12 Hours Later
G1 M M S G2 Total number of mitotic figures S G2
G1 M M S G2 Total number of mitotic figures Total number of labeled mitotic figures S G2
G1 M G2 S
G1 M G2 S
Go G1 M G2 S
G1 M G2 S S-phase cells are labeled after a short “pulse” with tritiated thymidine
Number of labelled mitoses G2 S G2 + M + G1
G1 M G2 S Restriction Point
DNA synthesis inhibitor M G1 G1 Cell Number G2 G2 S S G2 + M S
DNA synthesis inhibitor M G1 G1 M Cell Number (time greater than G2 + M + G1) G2 G2 S S G2 + M S
DNA synthesis inhibitor M G1 G1 M Cell Number (time greater than G2 + M + G1) G2 G2 S S G2 + M S
Release these cells from inhibition, and count cell number DNA synthesis inhibitor M G1 G1 M Cell Number G2 (time greater than G2 + M + G1) G2 S S G2 + M S
Release these cells from inhibition, and count cell number DNA synthesis inhibitor M G1 G1 M Cell Number G2 (time greater than G2 + M + G1) G2 S S G2 + M S
Release these cells from inhibition, and count cell number DNA synthesis inhibitor M G1 G1 M Cell Number G2 (time greater than G2 + M + G1) G2 S S G2 + M S
DNA synthesis inhibitor M G1 G1 M Cell Number G2 (time greater than G2 + M + G1) G2 S S G2 + M S Release these cells from inhibition, and count cell number
G1 M Cell number G2 • DNA • inhib S S + G2 + M
G1 G1 M G1 M M Cell number G2 G2 G2 • DNA • inhib S +DNA inhib S S S + G2 + M
G1 G1 M G1 M M Cell number G2 G2 G2 • DNA • inhib S +DNA inhib S S S + G2 + M
G1 G1 M G1 M M Cell number G2 G2 G2 • DNA • inhib S +DNA inhib S S S + G2 + M
G1 G1 M G1 M M Cell number G2 G2 G2 • DNA • inhib S +DNA inhib S S S + G2 + M Release these cells from inhibition, and count cell number
G1 G1 G1 M M M Cell number G2 G2 G2 • DNA • inhib S +DNA inhib S S S + G2 + M Release these cells from inhibition, and count cell number
Cell number Control early mid-E mid-L late fluorescence intensity G1 S G2
RATE cpm G1 S G2
RATE AMOUNT 2X cpm 1X G1 S G2 M
3H TdR Synchronize Cells, release Into 3H-TdR for Three hours
BudR 3H TdR Let grow several generations, then re-synchronize, label with BudR for three hours Synchronize Cells, release Into 3H-TdR for Three hours