Phenobarbital induction of mouse Cyp269 and Cyp2b10 genes

Phenobarbital (PB) induces the hepatic expression of some members of the CYP2B gene subfamily. A PB responsive element (BPRE) located within positions -2318 to -2155 of CYP2B2 inediated PB induction after in situ direct injection into rat liver (Park et al., JBC, 271. 23725-23728, 1996), The mouse Cyp2b9 sequence from position -925 to -759 by is 73% similar to that of the rat CYP2B2 PBRE. Using in situ direct injections in to the rat liver. Constructs having three copies of Cyp2b9 PBRE, were not induced by PB A 1 kb distal promoter fragment, from 4343 to 2423 of mouse Cyp2b10, has been isolated from genomic mouse DNA by PCR. This fragment contains a PBRE like sequence located at position -2423 to -2256. The Cyp2b10 PBRE sequence is 91% similar to rat CYP2B2 PBRE compared to 84% for the entire sequence from 4343 tp -2423. Sequence differences between Cyp2b9 and CYP2B2 or Cyp2b10 might explain the lower in vivo PB responsiveness of CYp2b9 compared to the other two genes and the lack of PB responsiveness of the Cyp2b9 PBRE in the in situ injection assay. The PB responsiveness of Cyp2b10 PBRE is presently being tested. Supported by NIH grant GM39360. INVITED MA Minority Travel Award.