Hepatocyte nuclear factor 4␣ (HNF-4␣), a liver-specific transcription factor, plays a significant role in many liver-specific functions, including lipid, glucose, drug, and ammonia metabolism, and also in embryonal liver development. However, its functions and regulation are not yet clearly understood. In this study, we constructed an adenovirus vector carrying rat HNF-4␣ cDNA and transfected the adenovirus to human hepatoma cells, HuH-7, to enforce expression of the exogenous HNF-4␣ gene. We

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... alyzed HNF-4␣-induced genes using cDNA microarray technology, which included over 9000 genes. As a result, 62 genes showed a greater than 2.0-fold change in expression level after the viral transfection. Fifty-six genes were consistently induced by HNF-4␣ overexpression, and six genes were repressed. To assess HNF-4␣ function, we attempted to classify the genes, which had been classified by their encoding protein functions in a previous report. We could classify 45 genes. The rest of the HNF-4␣-sensitive genes were unclassified (4 genes) or not identified (13 genes). Among the classified genes, almost half of the induced genes (26 of 40) were related to metabolism genes and particularly to lipid metabolism-related genes. This cDNA microarray analysis showed that HNF-4␣ is one of the central liver metabolism regulators.