The effect of Ink4a-Arf locus on cell growth and Tyr enzymatic activity. (A) Cell growth of Ink4a-Arf -/- (open circles), Ink4a-Arf +/- (closed circles) and Ink4a-Arf +/+ (crosses) melanocytes. Each point represents one subculture step and represents the mean count of cells from three replicates. (B) Tyrosine hydroxylase activity in albino melan-c (white bars), [Ink4a-Arf +/-; Tyrp1 B / Tyrp1 B ] (dark-grey bars), [Ink4a-Arf -/- ; Tyrp1 B / Tyrp1 B ] (light-grey bars) and melan-a (black bars) cells. (C) Melanin content in the same cellular types, as in (B). Bars represent the mean value (+/- SD) from three replicates. Tyrosinase activity and melanin content were measured in melanocyte primary cultures at passage 8 (~day 70 of culture). Statistically significant differences (t-Student test) are indicated as follows: * p < 0,1; ** p < 0,01; *** p < 0,001.
Lavado et al. BMC Cell Biology 2005 6:18 doi:10.1186/1471-2121-6-18