PT  - JOURNAL ARTICLE
AU  - Dan Li
AU  - Roger Gaedigk
AU  - Steven N. Hart
AU  - J. Steven Leeder
AU  - Xiao-bo Zhong
TI  - The Role of CYP3A4 mRNA Transcript with Shortened 3′-Untranslated Region in Hepatocyte Differentiation, Liver Development, and Response to Drug Induction
AID  - 10.1124/mol.111.074393
DP  - 2012 Jan 01
TA  - Molecular Pharmacology
PG  - 86--96
VI  - 81
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/81/1/86.short
4100  - http://molpharm.aspetjournals.org/content/81/1/86.full
SO  - Mol Pharmacol2012 Jan 01; 81
AB  - Cytochrome P450 3A4 (CYP3A4) metabolizes more than 50% of prescribed drugs. The expression of CYP3A4 changes during liver development and may be affected by the administration of some drugs. Alternative mRNA transcripts occur in more than 90% of human genes and are frequently observed in cells responding to developmental and environmental signals. Different mRNA transcripts may encode functionally distinct proteins or contribute to variability of mRNA stability or protein translation efficiency. The purpose of this study was to examine expression of alternative CYP3A4 mRNA transcripts in hepatocytes in response to developmental signals and drugs. cDNA cloning and RNA sequencing (RNA-Seq) were used to identify CYP3A4 mRNA transcripts. Three transcripts were found in HepaRG cells and liver tissues: one represented a canonical mRNA with full-length 3′-untranslated region (UTR), one had a shorter 3′-UTR, and one contained partial intron-6 retention. The alternative mRNA transcripts were validated by either rapid amplification of cDNA 3′-end or endpoint polymerase chain reaction (PCR). Quantification of the transcripts by RNA-Seq and real time quantitative PCR revealed that the CYP3A4 transcript with shorter 3′-UTR was preferentially expressed in developed livers, differentiated hepatocytes, and in rifampicin- and phenobarbital-induced hepatocytes. The CYP3A4 transcript with shorter 3′-UTR was more stable and produced more protein compared with the CYP3A4 transcript with canonical 3′-UTR. We conclude that the 3′-end processing of CYP3A4 contributes to the quantitative regulation of CYP3A4 gene expression through alternative polyadenylation, which may serve as a regulatory mechanism explaining changes of CYP3A4 expression and activity during hepatocyte differentiation and liver development and in response to drug induction.