Figure 1.

(a) Long-range DD-PCR of mock-treated keratinocyte RNA (lanes 1 and 2), tazarotene-treated keratinocyte RNA (lanes 3 and 4), and normal HeLa cell RNA as a control (lanes 5 and 6). The cDNA fragment identified as TIG3 (arrow) appears in lanes 3 and 4 but not in the other lanes. (b) Northern blot analysis of TIG3 expression in mock-treated (lane 1) or tazarotene-treated (lane 2) primary human foreskin keratinocytes. Cells were cultured in keratinocyte growth medium without serum until confluent, then were mock-treated or treated with 10⁻⁶ M tazarotene for 3 days. Cells were harvested, and 15 μg of total RNA was analyzed. The blot then was stripped and reprobed with GAPDH. (c) Semiquantitative reverse transcription–PCR analysis of week 2 biopsies from patients treated with topical tazarotene gel. The TIG3 message was detected initially at cycle 24 in treated biopsies but was not detected until cycle 26 in control untreated biopsies. (d) Multiple sequence alignment showing homology between TIG3, H-rev 107, and rat H-rev 107 (R-rev 107). (e) Western blot analysis of 15 μg of protein extract from mock-treated T47D cells (lane 1), T47D cells treated for 2 days with 1 μM tazarotene (lane 2), and ECR-293-TIG3 cells induced for 24 hours with 1 μM muristerone A (lane 3). Standards indicate the TIG3 protein runs at an apparent molecular mass of 18 kDa.