YY1 is required for melanocyte survival and the expression of melanocyte differentiation markers in vitro.

<p>(A,E) Knockdown of endogenous YY1 (A) and MITF (E) in MALME-3M cells. MALME-3M cells were infected with lentivirus carrying YY1 shRNA (yy1shR#1 & #6), MITF shRNA (mitfshR#4 & #5) or control shRNA (shLuc). After overnight infection, cells were selected with puromycin for 3 days. Total RNA and cell lysates were harvested for mRNA and protein measurements by RT-qPCR and western blotting. mRNA levels were normalized to β-actin (actB). (B) Growth curve of YY1 knockdown MALME-3M cells. After 3 days of puromycin selection of YY1 knockdown and control cells as in (A), cells were re-seeded at 1×10⁵ per 6 cm plate. Cell numbers were counted every other day. (C) Growth curve of YY1 knockdown HFM cells. HFM were infected and selected with puromycin as in (A). After puromycin selection, cell numbers were counted on days 0, 3, 5, 7. (D,F) mRNA levels were quantitated for <i>KIT</i> and multiple melanocyte differentiation genes in YY1 (D) and MITF (F) knockdown cells. Error bars represent s.d. of triplicates. *, p<0.05; **, p<0.01 (Student t-test).