Localization of cytochrome P1-450 and P3-450 genes to mouse chromosome 9.

Treatment of mice with polycyclic aromatic hydrocarbons results in the induction of P1-450 and P3-450 forms of cytochrome P-450. The genes for both cytochromes have recently been cloned and shown to be coordinately regulated by the Ah receptor. The mouse analogues of P1-450 and P3-450 can be distinguished from their hamster counterparts by Southern blot analysis with Kpn I-digested DNA fragments. DNA from hamster-mouse somatic cell hybrids that have selectively lost mouse chromosomes was used in Southern blots to map the location of the two mouse genes. Chromosome segregation analysis of 12 hybrid clones demonstrated that the structural genes for both P1-450 and P3-450 can be assigned to mouse chromosome 9.