EXPRESSION OF CYTOCHROME P450RAI (CYP26) IN HUMAN FETAL HEPATIC AND CEPHALIC TISSUES

PCR amplifications with two sets of degenerate primers that were targe ted to CYP26-specific regions were performed with cDNAs from human fet al liver and brain as templates. PCR products were purified, cloned, s equenced and analyzed with the BLAST program. Our results revealed exp ression of CYP26 in both human fetal liver and brain. Furthermore, hum an fetal CYP26 cDNA exhibited 99.2%-100% nucleotide sequence identity to its adult counterpart. Novel isoforms, that would have indicated ad ditional CYP26 genes, were not found. A Northern blot containing poly( A(+))RNAs from 43 human adult and 7 human fetal tissues was tested for CYP26 expression, We were able to detect CYP26 message in most tissue s but hybridization signals varied in intensity. Highest levels of tra nscription were in adult liver, heart, pituitary gland, adrenal gland, placenta and regions of the brain. CYP26 expression in fetal tissues was strongest in the brain and comparable with message levels in adult tissues. (C) 1998 Academic Press.