Carol Greider and Liz Blackburn (Cell 43:405, 1985)
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Greider and Liz Blackburn (Cell 43:405, 1985) omere-extending enzyme would solve the end-replication problem. t does one really exist? ng biochemical evidence of telomerase from Tetrahymena extracts tion of the macronucleus includes extensive breaking romosomes to make new, small chromosomes. will need new telomeres, high levels of telomerase would be expected! mena telomeres are (TTGGGG) n
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Carol Greider and Liz Blackburn (Cell 43:405, 1985) A telomere-extending enzyme would solve the end-replication problem. But does one really exist? Seeking biochemical evidence of telomerase from Tetrahymena extracts Formation of the macronucleus includes extensive breaking - PowerPoint PPT Presentation
Transcript of Carol Greider and Liz Blackburn (Cell 43:405, 1985)
Carol Greider and Liz Blackburn (Cell 43:405, 1985)
A telomere-extending enzyme would solve the end-replication problem.But does one really exist?
Seeking biochemical evidence of telomerase from Tetrahymena extracts
Formation of the macronucleus includes extensive breaking of chromosomes to make new, small chromosomes.
These will need new telomeres, so high levels of telomerase would be expected!
Tetrahymena telomeres are (TTGGGG)n
Simple assay:Tetrahymena extract
(TTGGGG)4 as one substrate
some combination of dNTPs
some are 32P-a-dNTP
run products on a gel.
With an assay, we can isolate the enzyme and characterize the protein & RNA
Andrea Bodnar et al. (Science 1998 279:349)
Will activation of telomerase prevent senescence?
Normal retinal pigment epithelial (RPE) cells lack telomerase activitydue to lack of TERT (protein) expressionhas low expression of TR (RNA)
Stably transfect RPE cells with TERT expressing plasmid
Telomerase assay:
Effect on time to senescence?
Population Doublings
Circles are control transfected RPE cells.Triangles are TERT-transfected RPE cells.
Black shapes represent cell lines that have senesced.Open shapes represent cell lines that have not senesced.
![University of WashingtonTelomerase and Cancer," by Carol W. Greider and Elizabeth H. Blackburn; SCIENTIFIC AMERICAN, February]. cells to replicate endlessly. The resulting cell immortality](https://static.fdocuments.us/doc/165x107/600131a851c34615f15cf061/university-of-washington-telomerase-and-cancer-by-carol-w-greider-and-elizabeth.jpg)
