cDNA clones for liver XXXX s from individual aroclor-treated @entity35 : constitutive expression of a new P-450 gene related to @entity109 -inducible forms.

@entity1447 @entity7772 @entity4921 @entity54457 @entity109 @entity35 @entity5954 @entity7773 @entity1473
Differential hybridization and screening with cloned inserts was used to identify two families of @entity1447 cDNA clones in libraries prepared from total liver poly(A)+RNA of individual @entity54457 -treated @entity35 . One family has cDNA inserts for the major @entity109 -inducible P-450s, @entity4921 and P-450e. Two types of P-450e inserts were identified. In addition, irregular inserts were characterized from two clones (PB23 and PB24) of this group. The other family has cDNA inserts for the major @entity5954 -inducible species, @entity7773 . No coding sequence restriction site variants were detected among 26 P-450d and @entity7772 inserts analyzed. The restriction map of the irregular 2.2-kb PB23 insert has a @entity4921 -like portion, followed by a 3' extension that hybridizes to RNAs of 2.7 and 4.8 kb, which are also detectable with a classical @entity4921 probe. The PB23 insert and the 2.7- and 4.8-kb RNAs presumably represent 3' extensions of @entity4921 mRNAs, polyadenylated at downstream sites. The 858-bp sequence of the PB24 insert encodes the @entity1473 -terminal portion of a @entity4921 protein. There is approximately 20% divergence at the polypeptide level between the PB24 and @entity4921 sequences; nevertheless, they share many essential features. A PB24-specific probe hybridizes to a 1.9-kb RNA species which is present in the liver of untreated @entity35 and which is not appreciably induced by @entity109 or Aroclor. The PB24 cDNA most likely represents a constitutive @entity1447 , related to @entity109 -inducible forms.
