title: Isolation and characterization of a cloned DNA sequence associated with the murine Ah locus and a 3-methylcholanthrene-induced form of cytochrome P-450.
abstract: Using partially purified mouse liver 23S mRNA known to be associated with the Ah locus and 3-methylcholanthrene-induced cytochrome P(1)-450, we synthesized double-stranded cDNA by the successive action of reverse transcriptase (RNA-directed DNA nucleotidyltransferase) and the Klenow A fragment of Escherichia coli DNA polymerase I. The double-stranded cDNA was inserted into pBR322 plasmid DNA by Pst I cleavage and homopolymeric "tailing" and cloned in E. coli LE392. Clone 46 hybridized with [(32)P]cDNA made from 23S mRNA from "Ah-responsive" C57BL/6N mice but did not hybridize with similarly prepared [(32)P]cDNA from "Ah-nonresponsive" DBA/2N mice. Clone 30 was positive, and clone 7 was negative, with both C57BL/6N and DBA/2N [(32)P]cDNA probes; these two clones were therefore used as "positive" and "negative" control clones, respectively. By translation-arrest experiments, clone 46 DNA and clone 30 DNA were shown to be associated with anti-P(1)-450- and anti-albumin-precipitable material, respectively. By agarose gel electrophoresis of Pst I digests, the clone 46 DNA insert was shown to be 1100 base pairs in total length and to contain one internal Pst I site. The cDNA made from total mRNA isolated from 3-methylcholanthrene-treated C57BL/6N mice hybridized to the two fragments of Pst I-digested DNA from clone 46, whereas similarly prepared cDNA from 3-methylcholanthrene-treated DBA/2N and control C57BL/6N and DBA/2N mice did not. Of 11 restriction endonucleases used, two (Pst I and Xba I) had sites within the clone 46 DNA insert. After hybridization of clone 46 (32)P-labeled nick-translated DNA to EcoRI fragments from A/HeJ mouse genomic DNA and fractionation by RPC-5 chromatography and gel electrophoresis, only one positive band (3-4 kilobase pairs appeared. These data demonstrate conclusively that pBR322 clone 46 DNA is associated with mRNA controlled by the murine Ah locus, presumably the structural gene encoding 3-methylcholanthrene-induced P(1)-450.
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008748:Methylcholanthrene / Q000494:pharmacology*; D051379:Mice; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D004274:DNA, Recombinant; D012333:RNA, Messenger; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D004262:DNA Restriction Enzymes