GeneNetwork and found that Cd14 is also a cis-regulated in the neocortex, mid-brain, prefrontal cortex, striatum, ventral tegmental area, bone, kidney, progenitor cells, and spleen among BXD mice (S1 Fig), which were generated using different microarray platforms. This data strongly supports that Cd14 is cis-regulated and suggest that a polymorphism in Cd14 between B6 and D2 mice affect the expression of Cd14 among BXD mice. Binding of a transcription factor to the promoter region of a gene is traditionally regarded as the main mechanism by which gene expression is regulated. Recent studies have shown, however, that polymorphisms within both intronic and exonic regions also play an important role in regulating gene expression [35, 36]. In our study we found three SNPs in the exonic regions of the Cd14 gene. At least one of these SNPs is responsible for Cd14 expression differences in multiple tissues among BXD mice.
