describes the relationship between the amount of methylation and luciferase

DNA methylation is commonly associated with a reduction of transcription. The following data come from a study of the impact of the location and extent of DNA methylation on gene activity in human cells.

A bacterial gene, luciferase, was cloned next to eukaryotic promoter fragments that were methylated to various degrees, in vitro. The chimeric plasmids were then introduced into tissue culture cells, and the luciferase activity was assayed. These data compare the degree of expression of luciferase with differences in the location of DNA methylation (Irvine et al., 2002. Mol. and Cell. Biol. 22: 6689–6696).

Which of the following describes the relationship between the amount of methylation and the expression of luciferase?


a. As methylation increases, luciferase expression increases.
 b. As methylation increases, luciferase expression decreases.
c. There is no relationship between the amount of methylation and the expression of luciferase