Transcript Telomerase and Topoisomerase

Telomerase
Targets for Cancer Treatment
The ends of chromosomes
• DNA polymerase has trouble copying the tips
of chromosomes- so why don’t we loose a
little bit of information each time the cell
replicates?
Telomeres- the ends of shoe laces
http://en.wikipedia.org/wiki/File:Telomere_ca
ps.gif
http://www.indiamart.com/srivaishnavi/shoeslaces-cords-and-tapes.html
DNA cap
• The DNA that is lost each time is “useless”
DNA- it is just repeating meaningless bases
• The length of this region keeps track of how
old the cell is
• Once the telomere gets too short the cell is
programmed- it knows- to die
Hayflick Limit
• A cell can only divide so many times before it
dies
• In the lab we keep track of how many plates
the cells have filled- we know when they’re
getting old
• People had observed this and didn’t know
why it happened
Telomerase
• Telomerase adds telomeres to the ends of
chromosomes- keeping a cell line alive longer
– A cell line is a family of cells that all came from a
single parent cell
• Some people have speculated that it could
turn back aging- why?
Cancer and telomerase
• What will be different about telomerase in
cancer cells?