Identification of age-dependently expressed genes in mouse liver by differential display–PCR analysis

The aim of this study was to identify genes expressed in an age-dependent manner in mouse (Mus musculus) liver. To search for age-dependently expressed genes, we used a fluorescence differential display–PCR (FDD–PCR) technique on total RNA extracted from mouse livers collected at seven different developmental stages. All differentially expressed cDNAs detected by FDD–PCR were reamplified, subcloned and sequenced, and six genes were confirmed to show age-dependent expression by quantitative real-time PCR analysis. Nucleotide sequence analyses showed that four of them had high homology with known genes (mitochondrial DNA, cytosolic aldehyde dehydrogenase, cell division cycle 2-like 5 and complement component 8 alpha polypeptide), and two with expressed sequence tags of unknown genes. The FDD–PCR technique was effective for detecting novel age-dependently expressed genes, and also for newly characterizing individual expression patterns of known genes. The age-dependent expression patterns of known genes revealed in this study may provide an opportunity to investigate the unknown physiological roles of the proteins they encode.