1. Identifying genes that confer resistance to ultraviolet radiation in the unicellular alga Chlamydomonas
Bryan LaBore
Northern Arizona University
Mentor: Dr. Karen VanWinkle-Swift

2. Why is this research important?
Prevent damage caused by UV (UV-C & UV-B)
Increasingly important with hole in ozone

3. Harmful Effects of UV-B Radiation
Damage to:
DNA mutations skin cancer
Protein defective enzymes altered metabolism
Lipids leaky membranes cell death
Protection from UV Radiation
Avoidance (sunscreens)
Common mechanism in plants
Melanin in humans, and topical sunscreens
Repair systems for DNA damage
Degrade and re-synthesize proteins and lipids

4. Chlamydomonas as a model
Unicellular green alga
Photosynthetic
Requires sunlight

5. How we got the uvs-1 mutant
mutagen
uvs-1 mutant

6. Wild-type vs. uvs-1 Survival at Various Doses of UV Radiation
WT uvs-1
0 sec
15 sec
30 sec
45 sec

7. How we got the sup mutant
mutagen
New sup mutation
Super sunscreen?
Super repair?

8. Suppressor mutants have regained resistance to UV radiation
UV Dose
(sec)

9. Now What? What does the suppressor mutation do?
We must isolate the sup mutation from the uvs mutation, which requires some basic genetics

10. A Review of Basic Genetics
Parentals
Recombinants

11. Genetic Analysis of the UV resistant suppressor mutants
Defective UV repair? (uvs)
Super sunscreen? (sup)
Normal UV repair (not uvs)
Normal sunscreen (not sup)
UV resistant
(uvs sup)
Normal
UV resistant
(uvs sup)
Normal
UV sensitive
(uvs)
SUPER UV resistant?!?!
(sup)

12. Further Research To Be Done
Isolate the sup mutation in all of the sup mutants
Perform further survival curves on the isolated mutants
Determine the mechanism behind each sup mutation (Super sunscreen? Super repair?)
Thank you to:
NASA
NAU
Dr. Nadine Barlow
Kathleen Stigmon
Dr. Karen VanWinkle-Swift

13. Questions?