To find out the key regulator(s) responsible to these down-regulated lipid metabolic genes in this module, we performed a transcription factor (TF) binding motifs enrichment analysis, and the result supported a pivotal role of HNF4, a master regulator for lipid mobilization and fatty acid beta-oxidation, as a core transcription factor for lipid metabolism change during Ecc15 infection (Figure 3C). This evidence concerns the gene HNF4A and infection.