Effects of Telomerase Activation on the Tissues of Prematurely-Aged Adult Mice
Telomerase Reactivation Reverses Tissue Degeneration in Aged Telomerase-deficient Mice
Jaskelioff et al., Nature, January 2011
This study looked at the effects of telomerase activation on the tissues of prematurely-aged adult mice. The telomerase enzyme, TERT-ER, is not expressed in the cells of these mice. The group induced (turned on) expression of TERT-ER by exposing mice to the compound 4-OHT, 4-hydroxytamoxifen (see definitions on next page). This treatment rebuilt the telomeres in the mice that had been damaged with age, as well as regenerated lost tissue.
Assignment – Answer in your own words and use complete sentences.
1. What kind of cellular events do aging and subsequent telomere loss cause?
Aging is mainly due to telomere loss which increases tissue degeneration, reduction of stem cells and general organ failure. There is also a loss in tissue repair. Telomere loss due to cell division eventually results in loss of DNA. (5 pts)
2. What is the hypothesis of this study? What are the controlled and uncontrolled variables?
The hypothesis of the study states that reactivation of endogenous telomerase activity in the cells would stop or reverse telomere degradation. An uncontrolled variable could be a spontaneous mutation this allows the mice to produce their own 4-OHT, activating telomerase. A controlled variable is 4-OHT. Controlling the levels of the 4-OHT allows you to control telomerase activity via the estrogen receptor. The receptors are engineered to only activate telomerase when the introduced 4-OHT accompanies the estrogen. (3 pts)
3. G0 cells were used as a control in this study. What is the difference between the G0 and G4 cells? (3 pts)
G0 cells were intercrossed to produce first generation mice homozygous for TERT-ER( G1-G4 cells) they show some telomerase activity. The G4 cells have no detectable telomerase activity making them perfect candidates for
Jaskelioff et al., Nature, January 2011
This study looked at the effects of telomerase activation on the tissues of prematurely-aged adult mice. The telomerase enzyme, TERT-ER, is not expressed in the cells of these mice. The group induced (turned on) expression of TERT-ER by exposing mice to the compound 4-OHT, 4-hydroxytamoxifen (see definitions on next page). This treatment rebuilt the telomeres in the mice that had been damaged with age, as well as regenerated lost tissue.
Assignment – Answer in your own words and use complete sentences.
1. What kind of cellular events do aging and subsequent telomere loss cause?
Aging is mainly due to telomere loss which increases tissue degeneration, reduction of stem cells and general organ failure. There is also a loss in tissue repair. Telomere loss due to cell division eventually results in loss of DNA. (5 pts)
2. What is the hypothesis of this study? What are the controlled and uncontrolled variables?
The hypothesis of the study states that reactivation of endogenous telomerase activity in the cells would stop or reverse telomere degradation. An uncontrolled variable could be a spontaneous mutation this allows the mice to produce their own 4-OHT, activating telomerase. A controlled variable is 4-OHT. Controlling the levels of the 4-OHT allows you to control telomerase activity via the estrogen receptor. The receptors are engineered to only activate telomerase when the introduced 4-OHT accompanies the estrogen. (3 pts)
3. G0 cells were used as a control in this study. What is the difference between the G0 and G4 cells? (3 pts)
G0 cells were intercrossed to produce first generation mice homozygous for TERT-ER( G1-G4 cells) they show some telomerase activity. The G4 cells have no detectable telomerase activity making them perfect candidates for