TYRP1 and infection: By contrast, MC1-R protein was induced almost immediately after infection of Mel1700 cells, but there was no appreciable impact on the already high baseline level of TRP-1 (Figure 7(b)); instead, there was a virus-induced increase in mRNA for MC1-R, POMC (the precursor of α-MSH), and xCT (gene name SLC7A11) (Figure 7(d)).