*2.8. RNA Extraction and RT-PCR*

Ectoine pre-treated (1.5 μM, 24 h) HaCaT cells were subjected to the TRIzol reagen<sup>t</sup> (Invitrogen, Carlsbad) for the isolation of total RNA from these cells. 1 μg of total RNA and the reagents supplied

by the SuperScript-III One-Step RT-PCR platinum *Taq* kit (Invitrogen, Carlsbad) were used in the PCR experiment with the Bio-Rad iCycler PCR instrument (Bio-Rad, Hercules, CA, United States). The forward and reverse primers for Nrf2 used were: F: 5-AAACCAGTGGATCTGCCAAC-3 , R-5-GCAATGAAGACTGGGCTCTC-3. The forward and reverse primers for GAPDH used were: F: 5-GCATCCTGGGCTACACTGA-3, R: 5-CCACCACCCTGTTGCTGTA-3. At the end of the experiment, PCR product was analyzed using 1% agarose gel. Then, it was visualized with ethidium bromide staining. As an internal control, we used GAPDH [22].
